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.
Alternating current (green curve).
^ Figure 1: Sine curve for one cycle of an alternating current.
  • Alternating Current Series Circut 10 February 2010 11:011 UTC www.stkate.edu [Source type: Academic]

^ Alternator Petrol Engine Electrical Operation I FIELD V OUT Alternator Excitation Curve (No Load) Alternator Alt Load R X L Internal Impedance Resistive Load V OUT V Z = Internal Impedance of the alternator V R = Internal Resistance of the alternator V L = Internal Reactance of the alternator I LOAD V R V Z V L V GEN Resistive Load  Load current and p.f.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

The horizontal axis measures time; the vertical, current or voltage.
.In alternating current (AC, also ac) the movement (or flow) of electric charge periodically reverses direction. An electric charge would for instance move forward, then backward, then forward, then backward, over and over again.^ Electric current in which electrons flow in one direction only.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ The unit of resistance to the flow of an electric current.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Current that regularly reverses the direction of its flow.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

In direct current (DC), the movement (or flow) of electric charge is only in one direction.
.Used generically, AC refers to the form in which electricity is delivered to businesses and residences.^ Used generically, AC refers to the form in which electricity is delivered to businesses and residences.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Primarily used to power an electric generator.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ And through the use of alternating current, Charles Proteus Steinmetz of General Electric was able to solve many of the problems associated with electricity generation and transmission.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.The usual waveform of an AC power circuit is a sine wave, however in certain applications, different waveforms are used, such as triangular or square waves.^ A device used in an electrical circuit that converts AC power to DC power.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ However in certain applications different waveforms are used, such as triangular or square waves.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The usual waveform of an AC power circuit is a sine wave , as this results in the most efficient transmission of energy.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.Audio and radio signals carried on electrical wires are also examples of alternating current.^ AC circuits, alternating current electricity .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ AC circuits: alternating current electricity .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ However, audio and radio signals carried on electrical wire are also examples of alternating current.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.^ In these applications, an important goal is often the recovery of information encoded (or modulated ) onto the AC signal.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

Contents

History

.
City lights viewed in a motion blurred exposure.
^ Jump to: navigation , search City lights viewed in a motion blurred exposure.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

The AC blinking causes the lines to be dotted rather than continuous.
Westinghouse Early AC System 1887
(US patent 373035)
A power transformer developed by Lucien Gaulard and John Dixon Gibbs was demonstrated in London in 1881, and attracted the interest of Westinghouse. .They also exhibited the invention in Turin in 1884, where it was adopted for an electric lighting system.^ The invention is especially suitable for use in systems containing large or high power wound rotor electric motors.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ When the vessel is initially started, a ship's electrical distribution system may have only  lights in operation.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: FILTERED WITH BAYES]

Many of their designs were adapted to the particular laws governing electrical distribution in the UK.
.In 1882, 1884, and 1885 Gaulard and Gibbs applied for patents on their transformer; however, these were overturned due to prior arts of Nikola Tesla and actions initiated by Sebastian Ziani de Ferranti.^ The system used today was devised by many contributors including Nikola Tesla , George Westinghouse , Lucien Gaulard , John Dixon Gibbs , and Oliver Shallenger from 1881 to 1889 .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ However, these tend to be more expensive and less efficient than transformers, and did not exist when Edison , Westinghouse and Tesla were designing their power systems.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ List of Tesla patents Nikola Tesla in popular culture Teslascope Electrical Experimenter .
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

.Ferranti went into this business in 1882 when he set up a shop in London designing various electrical devices.^ The device that converts electricity into another form of energy, such as heat, light, or motion.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ Dynamo - A device that changes mechanical energy into electrical energy.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ A semiconductor device that controls various modes of on/off states in electrical systems.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.Ferranti believed in the success of alternating current power distribution early on, and was one of the few experts in this system in the UK. In 1887 the London Electric Supply Corporation (LESCo) hired Ferranti for the design of their power station at Deptford.^ Transmission, distribution, and domestic power supply .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Includes the theory of alternating current and power.
  • PCC Catalog 10 February 2010 11:011 UTC www.pcc.edu [Source type: Reference]

^ One circuit is the three-phase  power circuit supplied from the distribution power panel.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: FILTERED WITH BAYES]

.He designed the building, the generating plant and the distribution system.^ Under the 2004 Power Marketing Plan, Western has changed its use of the CVP transmission system for the delivery of CVP northern power plants generation from an annual peak to monthly peaks for rate design purposes.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ Essentials of Distributed Generation Systems - Now owners, engineers, and electricians can quickly come up to speed on the five most prominent distributed generation technologies with Essentials of Distributed Generation Systems.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ Solar Power in Building Design - Solar Power in Building Design is a complete guide to designing, implementing, and auditing energy-efficient, cost-effective solar power systems for residential, commercial, and industrial buildings.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.On its completion in 1891 it was the first truly modern power station, supplying high-voltage AC power that was then "stepped down" for consumer use on each street.^ Steps AC voltage up or down, depending on the application.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Near the loads, the transmission voltage is stepped down to the voltages used by equipment.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The ultimate solution was to supply high-voltage AC power and transform it down in voltage at substations.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

.This basic system remains in use today around the world.^ As far as the actual lights themselves go the original lamp ( see picture below ) is still the basic lamp in use today.

^ Fluorescent lighting was basically not thought of UNTIL the 1950's ( see below ) AND Quartz Iodine lamps that became in use around the same time.

^ His "Tesla coil" is used today in labs around the world, and is used for things like detecting leaks in vacuum apparatus.

.Many homes all over the world still have electric meters with the Ferranti AC patent stamped on them.^ If, instead, you decide to use AC throughout your home, you would still need the DC photo panels and/or wind-generator, and the DC batteries.
  • Citizens For Renewable Energy, CFRE - FAQs 10 February 2010 11:011 UTC www.web.net [Source type: FILTERED WITH BAYES]

^ Despite having sold his AC electricity patents, Tesla was destitute and died with significant debts.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ From basic electricity through AC theory, transformers, and motor controls, all aspects of a typical electrical curriculum are explored in a single volume.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

William Stanley, Jr. designed one of the first practical devices to transfer AC power efficiently between isolated circuits. .Using pairs of coils wound on a common iron core, his design, called an induction coil, was an early transformer.^ Using pairs of coils wound on a common iron core, his design, called an induction coil , was an early precursor of the modern transformer .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Iron core coils have two types of losses, hysteresis loss and eddy current loss: .

^ A one-stop reference covering the theory, design tools, and techniques necessary to create the Tesla coil using modern materials.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.The AC power system used today developed rapidly after 1886, and includes key concepts by Nikola Tesla, who subsequently sold his patent to George Westinghouse.^ It was an historic event as Tesla and George Westinghouse introduced visitors to AC power by using it to illuminate the Exposition.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ The system used today was devised by many contributors including Nikola Tesla , George Westinghouse , Lucien Gaulard , John Dixon Gibbs , and Oliver Shallenger from 1881 to 1889 .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.Lucien Gaulard, John Dixon Gibbs, Carl Wilhelm Siemens and others contributed subsequently to this field.^ The system used today was devised by many contributors including Nikola Tesla , George Westinghouse , Lucien Gaulard , John Dixon Gibbs , and Oliver Shallenger from 1881 to 1889 .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity efficiently over long distances even though Edison attempted to discredit alternating current as too dangerous during the War of Currents.^ AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Grid - The layout of an electrical distribution system.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Identify common uses of alternating current.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.The first commercial power plant in the United States using three-phase alternating current was at the Mill Creek hydroelectric plant near Redlands, California, in 1893 designed by Almirian Decker.^ The first modern commercial power plant using three-phase alternating current was at the Mill Creek hydroelectric plant near Redlands, California in 1893.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Identify common uses of alternating current.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ While there, he studied the uses of alternating current.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

.Decker's design incorporated 10,000-volt three-phase transmission and established the standards for the complete system of generation, transmission and motors used today.^ Most AC motors are three phase.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

^ The invention is especially suitable for use in systems containing large or high power wound rotor electric motors.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.The Jaruga power plant in Croatia was set in operation on 28 August 1895, [1].^ The power detector 22 is especially desirable for use where additional power output is obtained by paralleling another motor generator set with the motor generator set illustrated in FIG. 1 (parallel operation).
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

.It was completed three days after the Niagara Falls plant, becoming the second commercial hydro power plant in the world.^ That company was the first customer of the AC power supplied by Westinghouse from Niagara Falls in the early 1900's.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ Solar Power in Building Design - Solar Power in Building Design is a complete guide to designing, implementing, and auditing energy-efficient, cost-effective solar power systems for residential, commercial, and industrial buildings.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ Morgan provided the finance as Tesla had successfully developed Alternating Current, and with the backing of Morgan had built the world's first Alternating Current Power station at Niagara Falls, in the U.S.A. Morgan was receptive to Tesla and thought that Tesla was onto something, having been impressed with Tesla's Alternating Current Power station.

.The two generators (42 Hz, 550 kW each) and the transformers were produced and installed by the Hungarian company Ganz.^ This generator produces two control signals.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Electricity Generation - The process of producing electric energy or the amount of electric energy produced by transforming other forms of energy, commonly expressed in kilowatthours (kWh) or megawatthours (MWh).
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Utility companies buy the electricity from QFs at the “avoided cost.” This is the cost it would take for the utility company to generate the amount of electricity the QF produces.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

.The transmission line from the power plant to the City of Šibenik was 11.5 kilometers (7.1 mi) long on wooden towers, and the municipal distribution grid 3000 V/110 V included six transforming stations.^ An inverter that is tied to a power grid or line.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ TTc = Total Transmission Capacity is the total transmission capacity under long-term contract between the Western Area Power Administration (Western) and other parties.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ Tranformers are essential in the electrical power transmission industry allowing power to be generated at one voltage and then stepped up to higher voltages for long distance transmission.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

.Alternating current circuit theory evolved rapidly in the latter part of the 19th and early 20th century.^ Chapter 21 - Alternating-Current Circuits .
  • Chapter 21 - Alternating-Current Circuits 10 February 2010 11:011 UTC www.mhhe.com [Source type: Reference]

^ Treatise on the theory of alternating currents,.

^ Alternating current circuit theory evolved rapidly in the latter part of the 19th and early 20th century.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Notable contributors to the theoretical basis of alternating current calculations include Charles Steinmetz, James Clerk Maxwell, Oliver Heaviside, and many others.^ Tesla's patents and theoretical work formed the basis of modern alternating current electric power (AC) systems, including the polyphase power distribution systems and the AC motor , with which he helped usher in the Second Industrial Revolution .
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

Calculations in unbalanced three-phase systems were simplified by the symmetrical components methods discussed by Charles Legeyt Fortescue in 1918.

Transmission, distribution, and domestic power supply

.AC voltage may be increased or decreased with a transformer.^ Transformer are used to increase or decrease voltages.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

^ In a triangle waveform, voltage increases gradually along a straight line to its maximum value, and then gradually decreases along a straight line to its lowest value, and then starts increasing again.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ AC stimulation may also decrease the quantity of chemotherapic drugs required to reduce tumor burden.
  • Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells 10 February 2010 11:011 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

.Use of a higher voltage leads to significantly more efficient transmission of power.^ There is thereby provided from the circuit 24 a composite error voltage which is used to control the speed of the motor so as to provide speed changes to accommodate changes in power factor.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Changing input power changes output power Increasing excitation drives load current lagging Reducing excitation drives load current leading Increasing input power increases output power Reducing input power reduces output power Output frequency and voltage do not change.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ Examples: Batteries and dc power supplies (such as the power supply built into the trainer that you use in lab) are DC voltage sources.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

The power losses in a conductor are a product of the square of the current and the resistance of the conductor, described by the formula P=I^2 R\,\!. This means that when transmitting a fixed power on a given wire, if the current is doubled, the power loss will be four times greater.
.Since the power transmitted is equal to the product of the current and the voltage (assuming no phase difference), the same amount of power can be transmitted with a lower current by increasing the voltage.^ Resistance on AC Current is in phase with voltage.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ It is easier to transmit to distant places at higher voltages as the current will be lower.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ The voltage across any resistor and the current through that resistor have the same phase angle.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

.Therefore it is advantageous when transmitting large amounts of power to distribute the power with high voltages (often hundreds of kilovolts).^ Therefore it is advantageous when transmitting large amounts of power to distribute the power with high voltages (often hundreds of kilovolts).
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC has at least four advantages over DC in a power distribution grid: 1.AC suffers from significantly less line loss than DC when transmitted over long distances because it is easy to step it up to extremely high voltages.
  • fUSION Anomaly. Alternating Current 10 February 2010 11:011 UTC fusionanomaly.net [Source type: FILTERED WITH BAYES]

^ So power companies convert alternating current to very high voltages for transmission (such as 1 million volts), then drop it back down to lower voltages for distribution (such as 1,000 volts), and finally down to 120 volts inside the house for safety.
  • HowStuffWorks "Direct Current vs. Alternating Current" 10 February 2010 11:011 UTC science.howstuffworks.com [Source type: FILTERED WITH BAYES]

.
High voltage transmission lines deliver power from electric generation plants over long distances using alternating current.
^ Power Plant - A facility where power, especially electricity, is generated.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Coal-Fired Power Plant - A power plant that uses coal as the fuel to generate electricity.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ The power produced by an electric current.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

These lines are located in eastern Utah.
.However, high voltages also have disadvantages, the main one being the increased insulation required, and generally increased difficulty in their safe handling.^ Period – The time required to turn the generators armature one complete revolution (360 degrees).

^ The most efficient use of electrical power is achieved by generating the power at one voltage then increasing the voltage to very high values for long distances and then reducing the voltage to lower values for safe use in industry and in the home.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

^ For the origin of the sinusoidally varying voltage in the mains supply, see Motors and generators .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

.In a power plant, power is generated at a convenient voltage for the design of a generator, and then stepped up to a high voltage for transmission.^ Under the 1994 Power Marketing Plan, Western was reserving transmission capacity based on the maximum output of directly connected CVP generating plants under normal operating conditions.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ The ultimate solution was to supply high-voltage AC power and transform it down in voltage at substations.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ A similar problem exists when the motor speed drops, say due to excessive loading or power plant supply voltage reductions.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

.Near the loads, the transmission voltage is stepped down to the voltages used by equipment.^ The voltage can then be stepped down for use in buildings, street lights, and so forth.
  • Alternating Current | FHSST: FREE HIGH SCHOOL SCIENCE TEXTS 10 February 2010 11:011 UTC www.fhsst.org [Source type: FILTERED WITH BAYES]

^ Near the loads, the transmission voltage is stepped down to the voltages used by equipment.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Three Phase Full Wave Rectified Alternating Current Three phase current is often used to power industrial equipment because it has more favorable power transmission and line loading characteristics.
  • Magnetizing Current 10 February 2010 11:011 UTC www.ndt-ed.org [Source type: Reference]

.Consumer voltages vary depending on the country and size of load, but generally motors and lighting are built to use up to a few hundred volts between phases.^ I don't use low voltage lighting.

^ Consumer voltages vary depending on the country and size of load, but generally motors and lighting are built to use up to a few hundred volts between phases.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For a sinusoidal voltage: V rms is useful in calculating the power consumed by a load.
  • Alternating current - Free Encyclopedia 10 February 2010 11:011 UTC www.wacklepedia.com [Source type: Reference]

.The utilization voltage delivered to equipment such as lighting and motor loads is standardized, with an allowable range of voltage over which equipment is expected to operate.^ The utilization voltage delivered to equipment such as lighting and motor loads is standardized, with an allowable range of voltage over which equipment is expected to operate.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Certain types of loads (e.g., lamps, motors) will draw a larger initial current because their impedance is lower at startup than during steady state operation.

^ Other parts of the world use different voltages ranging from 100VAC to 240VAC, and of course, heavy equipment anywhere can use much higher voltages.
  • Direct and Alternating Current 10 February 2010 11:011 UTC www.pcguide.com [Source type: FILTERED WITH BAYES]

.Standard power utilization voltages and percentage tolerance vary in the different mains power systems found in the world.^ A feedback loop that maintains output power in a specified range, or near a specified value, under variable conditions (such as weakening battery voltage, say).
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ A "world system" for "the transmission of electrical energy without wires" that depends upon the electrical conductivity was proposed in which transmission in various natural mediums with current that passes between the two point are used to power devices.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ At the 1893 World's Fair in Chicago, and then more spectacularly at Niagara Falls , the practicality of AC power systems was demonstrated.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

.Modern high-voltage, direct-current electric power transmission systems contrast with the more common alternating-current systems as a means for the efficient bulk transmission of electrical power over long distances.^ AC circuits, alternating current electricity .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ AC circuits: alternating current electricity .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ This produces an electrical voltage vertical to the current direction and the magnetic field.
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

.HVDC systems, however, tend to be more expensive and less efficient over shorter distances than transformers.^ Hybrid Electric Vehicle (HEV) Technology - Hybrid Electric Vehicle Technology provides foundational information about vehicles that use more than one propulsion technology to power a drive system.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ A solid state device that is less conductive than a conductor, but more conductive than an insulator.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ This will allow the use of high tension DC transmission lines which are more efficient than AC at a given voltage.
  • Our Grid: Powering Our 21st Century Lives With a 19th Century Design | Popular Science 10 February 2010 11:011 UTC www.popsci.com [Source type: General]

.Transmission with high voltage direct current was not feasible when Edison, Westinghouse and Tesla were designing their power systems, since there was then no way to economically convert AC power to DC and back again at the necessary voltages.^ A device that converts AC into DC. .
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ For example, v represents AC voltage, and i represents AC current.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ To convert into direct current.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.Three-phase electrical generation is very common.^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ The output of this generator may be for example 450 volts, three-phase 400 Hz power.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ A type of AC power that is generated with three waveforms that are not in phase with each other.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.Three separate coils in the generator stator are physically offset by an angle of 120° to each other.^ A type of AC power that is generated with three waveforms that are not in phase with each other.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ In the first experiment a drum-armature was provided with two coils at right angles to each other, and the ends of these coils were connected to two pairs of insulated contact-rings as usual.
  • "A New System of Alternate Current Motors and Transformers" byNikola Tesla 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: FILTERED WITH BAYES]

^ (P=V x I) Induction motors are simpler and cheaper than DC motors Voltage Generation N S V Generating an AC Voltage N S Generating an AC Voltage Time-> Volts + - Generating an AC Voltage Time-> N S Volts + - Generating an AC Voltage Time-> N S Volts + - Generating an AC Voltage Time-> N S Volts + - N S Generating an AC Voltage Time-> Volts + - Generating an AC Voltage Time-> N S Volts + - N S V Generating a AC Voltage 3-Phase N S Time-> Require: Three sets of coils physically displaced from each other by 120º electrical .
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

.Three current waveforms are produced that are equal in magnitude and 120° out of phase to each other.^ A type of AC power that is generated with three waveforms that are not in phase with each other.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ At any other value of line current, there are two values of excitation current that can produce this.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.If the load on a three-phase system is balanced equally among the phases, no current flows through the neutral point.^ Circuit(s) - A conductor or a system of conductors through which electric current flows.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ When the triggering potential of the uni-junction transistor is reached, the uni-junction fires and current flows through the resistor 242.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Hysteresis loss is due to the energy consumed in reversing the direction of the magnetic field of the iron core as the direction of current flow through the winding changes.

.Even in the worst-case unbalanced (linear) load, the neutral current will not exceed the highest of the phase currents.^ It has a high efficiency of about 90% at the rated output and can maintain the same efficiency even under part load operation in the case of a multi jet design.
  • Citizens For Renewable Energy, CFRE - FAQs 10 February 2010 11:011 UTC www.web.net [Source type: FILTERED WITH BAYES]

^ Three-phase synchronous machines • effects of load changes • effects of excitation change • load/current characteristics 12.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ Another special case is that in which the voltage and current are out of phase by 90: this is an important case because when this happens, no power is lost in the circuit.
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

Non-linear loads (e.g. computers) may require an oversized neutral bus and neutral conductor in the upstream distribution panel to handle harmonics. .Harmonics can cause neutral conductor current levels to exceed that of one or all phase conductors.^ Looking at the relative phase, the voltage across the capacitor is 90, or one quarter cycle, behind the current.
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ Such phase control of the rotor current is provided by control driver circuits 36, one for each of the windings of the rotor.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ But opposition to a current's flow may be caused in more than one way.
  • "Phenomena of Alternating Currents of Very High Frequency" 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: Original source]

.For three-phase at utilization voltages a four-wire system is often used.^ This voltage is used in measuring systems and sensors .
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

^ A type of rectifier that uses a three-phase AC electric power source to produce a relatively smooth DC. Three-phase rectifiers provide much smoother DC output voltage than single-phase rectifiers.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.When stepping down three-phase, a transformer with a Delta (3-wire) primary and a Star (4-wire, center-earthed) secondary is often used so there is no need for a neutral on the supply side.^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ The ultimate solution was to supply high-voltage AC power and transform it down in voltage at substations.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ Referring more particularly to FIG. 1, there is shown a three-phase wound rotor motor 10.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

.For smaller customers (just how small varies by country and age of the installation) only a single phase and the neutral or two phases and the neutral are taken to the property.^ Application: clocks record players timers recorders communications servo installations Two main types: Reluctance motor Hysteresis motor Reluctance Motor Stator Stator same as a single phase, split phase motor.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ Other Components: The costs of other components, such as mounts and wires, are highly variable and depend on how you set up your installation.
  • Citizens For Renewable Energy, CFRE - FAQs 10 February 2010 11:011 UTC www.web.net [Source type: FILTERED WITH BAYES]

^ Electricity 3: Power Generation, and Delivery - Designed for both novice and practicing electrical workers, Electricity: Power Generation and Delivery, 9th Edition , explores various types of generators and the delivery of single phase and three-phase power to the customer site.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.For larger installations all three phases and the neutral are taken to the main distribution panel.^ Star Generator / Transformer / Motor A C B S F S F S F S F S F S F B A C A C B Motor Star Why isn’t a neutral run to a balanced three phase Star connected load?
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

^ V 0V N 0A A C B Motor Star A B C The neutral is not connected to a balanced three phase star connected load.
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

.From the three-phase main panel, both single and three-phase circuits may lead off.^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ The output of this generator may be for example 450 volts, three-phase 400 Hz power.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Input voltage which may for example be 440 volts, three phase at 60 Hz is applied to the stator windings of the motor.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

.Three-wire single phase systems, with a single center-tapped transformer giving two live conductors, is a common distribution scheme for residential and small commercial buildings in North America.^ A residential photovoltaic system is a distributed system.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ Photovoltaic Systems is a comprehensive guide to the design, installation, and evaluation of residential and commercial photovoltaic (PV) systems.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.This arrangement is sometimes incorrectly referred to as "two phase". A similar method is used for a different reason on construction sites in the UK. Small power tools and lighting are supposed to be supplied by a local center-tapped transformer with a voltage of 55 V between each power conductor and earth.^ Voltage - The difference in electrical potential between any two conductors or between a conductor and ground.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ That simple result comes about because the two voltages are both in phase with the current, so their phasors are parallel.
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

^ It can be transformed to higher and lower voltages (with transformers) allowing the transmission and distribution of power with lower losses.
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

.This significantly reduces the risk of electric shock in the event that one of the live conductors becomes exposed through an equipment fault whilst still allowing a reasonable voltage of 110 V between the two conductors for running the tools.^ Voltage - The difference in electrical potential between any two conductors or between a conductor and ground.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ An undesirable feedback condition caused by two or more circuits sharing a common electrical line, usually a grounded conductor.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ A method of preventing oxidation (rusting) of exposed metal structures, such as bridges and pipelines, by imposing between the structure and the ground a small electrical voltage that opposes the flow of electrons and that is greater than the voltage present during oxidation.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.A third wire, called the bond (or earth) wire, is often connected between non-current-carrying metal enclosures and earth ground.^ Originally, electric power was distributed by single DC lines (the ground was ground , and it carried the return current).
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ Any conductor that carries AC current has some inductance, however, an inductor is usually a coil of wire.

^ The wire used in the inductor must be large enough to carry the current required by the load to prevent burn out.

.This conductor provides protection from electric shock due to accidental contact of circuit conductors with the metal chassis of portable appliances and tools.^ A conductor within a module or other means of connection which provides an electrical interconnection between the solar cells.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Circuit(s) - A conductor or a system of conductors through which electric current flows.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ An undesirable feedback condition caused by two or more circuits sharing a common electrical line, usually a grounded conductor.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.Bonding all non-current-carrying metal parts into one complete system ensures there is always a low electrical impedance path to ground sufficient to carry any fault current for as long as it takes for the system to clear the fault.^ Even fresh water has significant > > > conductivity and there is necessarily an electric current (more > > > properly, a flux of current density).
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ There are two causes for it, one of which is always present, the other sometimes only.
  • "Phenomena of Alternating Currents of Very High Frequency" 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: Original source]

^ Even fresh water has significant > > conductivity and there is necessarily an electric current (more > > properly, a flux of current density).
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

.This low impedance path allows the maximum amount of fault current, causing the overcurrent protection device (breakers, fuses) to trip or burn out as quickly as possible, bringing the electrical system to a safe state.^ An electric field will not cause harm without a current > > path.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ A device that controls various modes of on/off states in electrical systems.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ The RMS value is the AC voltage or current that will cause the same amount of heat in a resistance as the equivalent DC voltage or current.

.All bond wires are bonded to ground at the main service panel, as is the Neutral/Identified conductor if present.^ This text gets to the root of all problems associated with grounding and bonding.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ Based on the 2008 NEC , this hands-on guide illustrates Code provisions concerning circuit and system grounding; grounding electrode systems and electrode conductors; enclosure, raceway, and service cabling grounding; bonding; equipment grounding and equipment grounding conductors; and much more...
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ System Grounding & Equipment Grounding Principles of Effective Grounding Service Neutrals and Grounding Lightning and Grounding - more .
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

AC power supply frequencies

.The frequency of the electrical system varies by country; most electric power is generated at either 50 or 60 Hz.^ Primarily used to power an electric generator.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ All of the information needed for a thorough understanding of Motor Controllers and their theory, operation, installation and maintenance of various electrical systems is provided.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ The frequency of these pulses thus may be from 2 to 20 Hertz (Hz) and can result in significant low frequency power pulses approaching frequencies at which the power generating system which provides power for driving the motor is mechanically or electrically resonant.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

See Mains power around the world. .Some countries have a mixture of 50 Hz and 60 Hz supplies, notably Japan.^ Electric current in which the direction of flow is reversed at frequent intervals--usually 100 or 120 times per second (50 or 60 cycles per second or 50//60 Hz).
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.A low frequency eases the design of low speed electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways, but also causes a noticeable flicker in incandescent lighting and an objectionable flicker in fluorescent lamps.^ This voltage will be at the slip frequency and vary from 60 Hz on locked rotor conditions to zero Hz when the motor is at desired operating speed.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ In this study, the application of alternating low-amperage electric treatment to effluent seawater was investigated for the large-scale disinfection of seawater.
  • Inactivation of Vibrio parahaemolyticus in Effluent Seawater by Alternating-Current Treatment 10 February 2010 11:011 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

^ The second cause alluded to, which possibly may not be present, is due to the tendency of a, machine of such high frequency td maintain a practically constant current.
  • "Phenomena of Alternating Currents of Very High Frequency" 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: Original source]

.16⅔ Hz power is still used in some European rail systems, such as in Austria, Germany, Norway, Sweden and Switzerland.^ The increase in CVP transmission rates from the existing rate is primarily due to an increase in O&M costs and a change in Western's use of the CVP transmission system under the 2004 Power Marketing Plan.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ The invention is especially suitable for use in systems containing large or high power wound rotor electric motors.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Water wheels are still used in some situations that do not require a fast-spinning turbine, such as for pumping water.
  • Citizens For Renewable Energy, CFRE - FAQs 10 February 2010 11:011 UTC www.web.net [Source type: FILTERED WITH BAYES]

The use of lower frequencies also provided the advantage of lower impedance losses, which are proportional to frequency. .The original Niagara Falls generators were built to produce 25 Hz power, as a compromise between low frequency for traction and heavy induction motors, while still allowing incandescent lighting to operate (although with noticeable flicker); most of the 25 Hz residential and commercial customers for Niagara Falls power were converted to 60 Hz by the late 1950s, although some 25 Hz industrial customers still existed as of the start of the 21st century.^ The motor system as set forth in claim 27 further including means responsive to the power produced by said generator for generating a fourth signal corresponding thereto, and means for adding said fourth signal to said first signal and applying the sum of said first and fourth signal to said control signal generator.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ Power-Generating Efficiency - The percentage of the total energy content of a power plant’s fuel which is converted into electric energy.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Alternating current originated with the accumulation of discoveries made in the 19th century by the electrical pioneers that developed the generator.

.Off-shore, military, textile industry, marine, computer mainframe, aircraft, and spacecraft applications sometimes use 400 Hz, for benefits of reduced weight of apparatus or higher motor speeds.^ There is thereby provided from the circuit 24 a composite error voltage which is used to control the speed of the motor so as to provide speed changes to accommodate changes in power factor.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ FIG. 6A illustrates the slip frequency voltage waveform for two conditions, namely when the slip frequency voltage has a frequency of 60 Hz during locked rotor conditions and when the motor is coming up to speed and slip frequency has reduced to 30 Hz.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ This voltage will be at the slip frequency and vary from 60 Hz on locked rotor conditions to zero Hz when the motor is at desired operating speed.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

Effects at high frequencies

.A direct current flows constantly and uniformly throughout the cross-section of a uniform wire.^ Unlike Direct Current, where current flows in one direction only, Alternating Current reverses its direction of current flow every half cycle of armature rotation.

^ Electric current in which electrons flow in one direction only.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ ELI. Maximum current flows when voltage crosses zero.

.An alternating current of any frequency is forced away from the wire's center, toward its outer surface.^ In the absence of thermal influences, low-frequency, low-intensity, alternating current (AC) directly affects cell proliferation without a significant deleterious contribution to cell survival.
  • Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells 10 February 2010 11:011 UTC www.ncbi.nlm.nih.gov [Source type: Academic]

^ This electric motor was the first step toward the successful application of alternating-current.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ Inductance of the coil Frequency of the alternating current The constant 2π = 6.28 .

.This is because the acceleration of an electric charge in an alternating current produces waves of electromagnetic radiation that cancel the propagation of electricity toward the center of materials with high conductivity.^ Any material that has a limited capacity for conducting an electric current.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Electromagnetic Waves - Radiation that consists of traveling waves of electric and magnetic disturbances.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ The power produced by an electric current.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

This phenomenon is called skin effect.
.At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths.^ "Tesla currents" when we really mean the high frequency currents."
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ What they detect, is the electrostatic force of the electric field on > > > their epethelial and ampullary structures, which couple capacitively; > > > there is no current flow.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ From 1893 to 1895, he investigated high frequency alternating currents.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

The skin depth is the thickness at which the current density is reduced by 63%. .Even at relatively low frequencies used for high power transmission (50–60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors.^ The frequency of these pulses thus may be from 2 to 20 Hertz (Hz) and can result in significant low frequency power pulses approaching frequencies at which the power generating system which provides power for driving the motor is mechanically or electrically resonant.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ In a practical wireless energy transmission system using this principle, a high-power ultraviolet beam might be used to form a vertical ionized channel in the air directly above the transmitter-receiver stations.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ The provisional formula rate for CVP NITS is based on the same revenue requirement that is used in the CVP firm and non-firm transmission formula rate.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

.For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.^ For example: Find the capacitive reactance of the following capacitors connected in parallel that have the values of 0.5 mfd, 0.25 mfd and 0.1 mfd ; the frequency is 60 Hz.

^ Any conductor that carries AC current has some inductance, however, an inductor is usually a coil of wire.

^ Most matter has resistance to the flow of electricity; the resistance is very small in a conductor like copper wire and very high for an insulator like a piece of mica.

.Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.^ This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Care must be taken that the secondary of a current transformer is not disconnected from its load while current is flowing in the primary, as the transformer secondary will attempt to continue driving current across the effectively infinite impedance .
  • CR4 - Thread: Non-Contact Sensing for Voltage and Current 10 February 2010 11:011 UTC cr4.globalspec.com [Source type: FILTERED WITH BAYES]

.This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows.^ The unit of resistance to the flow of an electric current.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ The root-mean-square ( rms ) value or effective value of an ac waveform is a measure of how effective the waveform is in producing heat in a resistance.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ The RMS value is the AC voltage or current that will cause the same amount of heat in a resistance as the equivalent DC voltage or current.

.The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to ohmic heating (also called I2R loss).^ The root-mean-square ( rms ) value or effective value of an ac waveform is a measure of how effective the waveform is in producing heat in a resistance.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ Power: The power in a purely resistive AC circuit can be determined using the same formulas as for DC circuits.

^ The RMS value is the AC voltage or current that will cause the same amount of heat in a resistance as the equivalent DC voltage or current.

Techniques for reducing AC resistance

.For low to medium frequencies, conductors can be divided into stranded wires, each insulated from one other, and the relative positions of individual strands specially arranged within the conductor bundle.^ A conductor within a module or other means of connection which provides an electrical interconnection between the solar cells.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Most matter has resistance to the flow of electricity; the resistance is very small in a conductor like copper wire and very high for an insulator like a piece of mica.

Wire constructed using this technique is called Litz wire. .This measure helps to partially mitigate skin effect by forcing more equal current flow throughout the total cross section of the stranded conductors.^ Circuit(s) - A conductor or a system of conductors through which electric current flows.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ When two or more capacitors are connected in series, the total capacitance is equal to the reciprocal of the sum of the reciprocals of the individual capacitors.

^ When two or more capacitors are connected in parallel, the total capacitance is equal to the sum of the individual capacitance’s.

.Litz wire is used for making high-Q inductors, reducing losses in flexible conductors carrying very high currents at lower frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers.^ At low frequencies, this loss is negligible, but is very noticeable at higher radio frequencies.

^ Mica dielectric capacitors are used in circuits that carry high radio frequency currents.

^ The switches are power semiconductors that can carry a large current and withstand a high voltage rating.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

Techniques for reducing radiation loss

.As written above, an alternating current is made of electric charge under periodic acceleration, which causes radiation of electromagnetic waves.^ Electromagnetic Waves - Radiation that consists of traveling waves of electric and magnetic disturbances.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Alternating current originated with the accumulation of discoveries made in the 19th century by the electrical pioneers that developed the generator.

^ And while I am at it, I might point out the incredible stupidity in the statement "The E-field exists, but it is merely associated with the intrinsically charged beta particles in the alternating current."
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

.Energy that is radiated represents a loss.^ These losses represent a very small amount of the total loss of energy in a capacitor.

.Depending on the frequency, different techniques are used to minimize the loss due to radiation.^ The effective emissivity is a different average of the same frequency-dependent absorptivity (the same as the frequency-dependent emissivity).
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ This is a very powerful technique, so the analysis of analog circuits is generally done in terms of frequency-dependent response to sinusoidal inputs.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ The term ``colored body'' is used to emphasize that there is a frequency dependence in the albedo, but the term ``grey body'' is sometimes nevertheless used for colored bodies simply to indicate that the important fact is that the albedo is intermediate.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

Twisted pairs

At frequencies up to about 1 GHz, pairs of wires are twisted together in a cable, forming a twisted pair. This reduces losses from electromagnetic radiation and inductive coupling. .A twisted pair must be used with a balanced signalling system, so that the two wires carry equal but opposite currents.^ The error signals E fh and E fl are used in the control signal generator 26, which is shown in FIG. 5, in order to generate control signals which operate the rotor current controls 32 and 34.
  • Alternating current motor system - Patent 3969659 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ A "world system" for "the transmission of electrical energy without wires" that depends upon the electrical conductivity was proposed in which transmission in various natural mediums with current that passes between the two point are used to power devices.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ Any conductor that carries AC current has some inductance, however, an inductor is usually a coil of wire.

Each wire in a twisted pair radiates a signal, but it is effectively cancelled by radiation from the other wire, resulting in almost no radiation loss.

Coaxial cables

.At frequencies above 1 GHz, unshielded wires of practical dimensions lose too much energy to radiation, so coaxial cables are used instead.^ Often used instead of joules when dealing with the energy released from food.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Solar Thermal Heating System - Systems using concentrating collectors to focus the sun's radiant energy onto or into receivers to produce heat.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

A coaxial cable has a conductive wire inside a conductive tube, separated by a dielectric layer. .The current flowing on the inner conductor is equal and opposite to the current flowing on the inner surface of the tube.^ Circuit(s) - A conductor or a system of conductors through which electric current flows.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ The opposition of a capacitor to the flow of alternating current is called capacitive reactance (Xc).

^ The opposition of an inductor or a coil to the flow of alternating current is called inductive reactance.

.The electromagnetic field is thus completely contained within the tube, and (ideally) no energy is radiation or coupling outside the tube.^ Light - Radiant electromagnetic energy that an observer can see.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Radiation - Any high-speed transmission of energy in the form of particles or electromagnetic waves.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ What they detect, is the electrostatic force of the electric field on > > > their epethelial and ampullary structures, which couple capacitively; > > > there is no current flow.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

Coaxial cables have acceptably small losses for frequencies up to about 20 GHz. .For microwave frequencies greater than 20 GHz, the losses (due mainly to the dissipation factor of the dielectric) become too large, making waveguides a more efficient medium for transmitting energy.^ Hysteresis loss is due to the energy consumed in reversing the direction of the magnetic field of the iron core as the direction of current flow through the winding changes.

^ Energy Efficiency - Refers to activities that are aimed at reducing the energy used by substituting technically more advanced equipment, typically without affecting the services provided.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Easier and cheaper to make than crystalline, but less efficient and slowly degrades over time.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

Waveguides

.Waveguides are similar to coax cables, as both consist of tubes, with the biggest difference being that the waveguide has no inner conductor.^ This device differed from other early X-ray tubes in that they had no target electrode.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

Waveguides can have any arbitrary cross section, but rectangular cross sections are the most common. .Because waveguides do not have an inner conductor to carry a return current, waveguides cannot deliver energy by means of an electric current, but rather by means of a guided electromagnetic field.^ The energy that cannot be returned to the electrical circuit is converted to heat.

^ An electric field will not cause harm without a current > > path.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ A conductor within a module or other means of connection which provides an electrical interconnection between the solar cells.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.Although surface currents do flow on the inner walls of the waveguides, those surface currents do not carry power.^ But thanks for making the point that this experiment was carried out in an aquatic environment, wherein such a field would result in a current flow.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ Originally, electric power was distributed by single DC lines (the ground was ground , and it carried the return current).
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

^ One ampere of current flowing at a potential of one volt produces one watt of power.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

Power is carried by the guided electromagnetic fields. The surface currents are set up by the guided electromagnetic fields and have the effect of keeping the fields inside the waveguide and preventing leakage of the fields to the space outside the waveguide.
.Waveguides have dimensions comparable to the wavelength of the alternating current to be transmitted, so they are only feasible at microwave frequencies.^ Enables checking of the frequency and duty ratio while alternating current/voltage measurement is being performed .
  • Handheld Measuring Instruments:Instrument products:Graphtec Corporation 10 February 2010 11:011 UTC graphteccorp.com [Source type: Academic]

^ Inductance of the coil Frequency of the alternating current The constant 2π = 6.28 .

^ From 1893 to 1895, he investigated high frequency alternating currents.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

.In addition to this mechanical feasibility, electrical resistance of the non-ideal metals forming the walls of the waveguide cause dissipation of power (surface currents flowing on lossy conductors dissipate power).^ Ohm - The unit of resistance to the flow of an electric current.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ The power produced by an electric current.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Circuit(s) - A conductor or a system of conductors through which electric current flows.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

At higher frequencies, the power lost to this dissipation becomes unacceptably large.

Fiber optics

.At frequencies greater than 200 GHz, waveguide dimensions become impractically small, and the ohmic losses in the waveguide walls become large.^ Note that the voltage across the Inductor and Capacitor is much greater than the applied voltage at the resonant frequency of the circuit.

Instead, fiber optics, which are a form of dielectric waveguides, can be used. .For such frequencies, the concepts of voltages and currents are no longer used.^ As such, the comparison above is no longer applicable.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ Therefore, you can use circuit rules that you already know--such as Ohm's Law, Kirchhoff's Voltage Law, and Kirchoff's Current Law--in pretty much the same way that you used them in DC circuits.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ Response: Western considered this comment, and the formula for determining regulation capacity is no longer part of the regulation and frequency response service formula rate.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

Mathematics of AC voltages

.
A sine wave, over one cycle (360°).
^ Recalling that one complete cycle of a sine wave is generated when a generator's rotor rotates through an angle of 360° (a full rotation), here's another way of plotting a sine wave: Here we're plotting voltage on the vertical axis, just as before, but now we're plotting degrees of the rotor's rotation on the horizontal axis.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ {Cycle} If we were to follow the changing voltage produced by a coil in an alternator from any point on the sine wave graph to that point when the wave shape begins to repeat itself, we would have marked exactly one \textit{cycle} of that wave.
  • Alternating Current | FHSST: FREE HIGH SCHOOL SCIENCE TEXTS 10 February 2010 11:011 UTC www.fhsst.org [Source type: FILTERED WITH BAYES]

^ The graph of current against time for one cycle or period T is the typical sine curve of Fig.
  • Alternating Current Series Circut 10 February 2010 11:011 UTC www.stkate.edu [Source type: Academic]

The dashed line represents the root mean square (RMS) value at about 0.707
.Alternating currents are accompanied (or caused) by alternating voltages.^ Character and Conditions of Service: Transmission service for three-phase, alternating current at 60 hertz, delivered and metered at the voltages and points of delivery or receipt, adjusted for losses, and delivered to points of delivery.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ Since capacitive reactance causes current to lead voltage and inductive reactance causes current to lag voltage, the two reactance’s are opposite in effect.

^ Both offer an opposition to alternating current, both are expressed in ohms, and both are equal to the voltage divided by current.

An AC voltage v can be described mathematically as a function of time by the following equation:
v(t)=V_\mathrm{peak}\cdot\sin(\omega t),
where
  • \displaystyle V_{\rm peak} is the peak voltage (unit: volt),
  • \displaystyle\omega is the angular frequency (unit: radians per second)
    • The angular frequency is related to the physical frequency, \displaystyle f (unit = hertz), which represents the number of cycles per second , by the equation \displaystyle\omega = 2\pi f.
  • \displaystyle t is the time (unit: second).
.The peak-to-peak value of an AC voltage is defined as the difference between its positive peak and its negative peak.^ What is the difference between ac and dc currents?
  • Voltage Sources and Electric Current 10 February 2010 11:011 UTC facstaff.gpc.edu [Source type: Reference]

^ Maximum or peak value of the voltage, in volts (V) .
  • Principles of alternating current 10 February 2010 11:011 UTC www.tina.com [Source type: Academic]

^ The peak-to-peak value is the difference between a waveform's positive peak value and its negative peak value.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

.Since the maximum value of sin(x) is +1 and the minimum value is −1, an AC voltage swings between + Vpeak and Vpeak.^ The maximum value reached by an ac waveform is called its peak value.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ The mathematical expression for a voltage sine wave with peak value V p is v = V p sin(θ) .
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ For a sine wave, to convert from peak values to rms values , use these equations: For voltages, V rms ≈ 0.707 × V p .
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

.The peak-to-peak voltage, usually written as Vpp or VP − P, is therefore Vpeak − ( − Vpeak) = 2Vpeak.^ The same law also applies to peak-to-peak values and rms values: I pp = V pp ÷ R and I rms = V rms ÷ R Of course, you can also rearrange any of these equations algebraically if you wish to solve for voltage or resistance.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ If the waveform is a voltage waveform, then its peak-to-peak value is also called its peak-to-peak voltage , abbreviated V pp .
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

Power and root mean square

The relationship between voltage and the power delivered is
p(t) = \frac{v^2(t)}{R} where R represents a load resistance.
.Rather than using instantaneous power, p(t), it is more practical to use a time averaged power (where the averaging is performed over any integer number of cycles).^ Tesla began to theorize about electricity and magnetism's power to warp, or rather change, space and time and the procedure by which man could forcibly control this power.
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ The clamp can be used to perform measurements on data lines and power lines.
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

^ Ultrawideband uses very low-powered, short-pulse radio signals many times in the picosecond duration range to transfer data over a very wide range of frequencies .
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

Therefore, AC voltage is often expressed as a root mean square (RMS) value, written as Vrms, because
P_{\rm time~averaged} = \frac{{V^2}_{\rm rms}}{R}.
For a sinusoidal voltage:
V_\mathrm{rms}=\frac{V_\mathrm{peak}}{\sqrt{2}}.
The factor \sqrt{2} is called the crest factor, which varies for different waveforms.
V_\mathrm{rms}=\frac{V_\mathrm{peak}}{\sqrt{3}}.
\displaystyle V_\mathrm{rms}=V_\mathrm{peak}.

Example

.To illustrate these concepts, consider a 230 V AC mains supply used in many countries around the world.^ AC electricity is more complicated than DC, so this unit will introduce some concepts and terms that we'll use for the rest of the course.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ Of these three representations, phasor diagrams are the probably the easiest to use and to understand, so they are widely used in AC circuit analysis.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ In practice, AC tends to refer to power supply (including what in Britain is called mains voltage) rather than to general electrical or communication signals, and these applications virtually always use a sinusoidally (time-)varying voltage of a single frequency.
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

It is so called because its root mean square value is 230 V. This means that the time-averaged power delivered is equivalent to the power delivered by a DC voltage of 230 V. To determine the peak voltage (amplitude), we can rearrange the above equation to:
 V_\mathrm{peak}=\sqrt{2}\ V_\mathrm{rms}.
For our 230 V AC, the peak voltage Vpeak is therefore \displaystyle 230 V 	imes\sqrt{2}, which is about 325 V. The peak-to-peak value \displaystyle V_{P-P} of the 230 V AC is double that, at about 650 V.
.Note that some countries use a frequency of 50 Hz, while others use a frequency of 60 Hz.^ High frequency oscillators for electro-therapeutic and other purposes, 1899 [50] .
  • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ For example: Find the capacitive reactance of the following capacitors connected in parallel that have the values of 0.5 mfd, 0.25 mfd and 0.1 mfd ; the frequency is 60 Hz.

^ Electric current in which the direction of flow is reversed at frequent intervals--usually 100 or 120 times per second (50 or 60 cycles per second or 50//60 Hz).
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

The calculation to convert from RMS voltage to peak voltage is independent of the frequency.

See also

Further reading

  • Willam A. Meyers, History and Reflections on the Way Things Were: Mill Creek Power Plant - Making History with AC, IEEE Power Engineering Review, February 1997, Pages 22–24

External links

  • "Alternating Current: Alternating Current". Interactive Java tutorial explaining alternating current. .(National High Magnetic Field Laboratory)
  • "AC/DC: What's the Difference?". Edison's Miracle of Light, American Experience.^ Edison had also never wanted to hear about Tesla's AC polyphase designs, believing that DC electricity was the future.
    • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

    ^ Electricity 4: AC/DC Motors, Controls and Maintenance - Obtain quick and easy access to information on DC and AC motors, various types of manual, magnetic, and electronic controls, and the installation and maintenance functions of each.
    • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

    ^ In an AC circuit, when an alternating voltage is applied to a coil in the circuit, the magnetic field created by the coil is constantly expanding and collapsing, causing a continuous back emf.

    .(PBS)
  • "AC/DC: Inside the AC Generator". Edison's Miracle of Light, American Experience.^ Edison had also never wanted to hear about Tesla's AC polyphase designs, believing that DC electricity was the future.
    • Nicola Tesla - Father of (AC) Alternating Current System - a knol by Neo ! 10 February 2010 11:011 UTC knol.google.com [Source type: FILTERED WITH BAYES]

    ^ Electricity 1: Devices, Circuits and Materials Electricity 2: Devices, Circuits and Materials Electricity 3: Power Generation, and Delivery Electricity 4: AC/DC Motors, Controls & Maintenance .
    • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

    .(PBS)
  • Kuphaldt, Tony R., "Lessons In Electric Circuits : Volume II - AC". March 8, 2003. (Design Science License)
  • Nave, C. R., "Alternating Current Circuits Concepts". HyperPhysics.
  • "Alternating Current (AC)". Magnetic Particle Inspection, Nondestructive Testing Encyclopedia.
  • "Alternating current". Analog Process Control Services.
  • Hiob, Eric, "An Application of Trigonometry and Vectors to Alternating Current". British Columbia Institute of Technology, 2004.
  • "Introduction to alternating current and transformers". Integrated Publishing.
  • "Wind Energy Reference Manual Part 4: Electricity". Danish Wind Industry Association, 2003.
  • Chan.^ AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity.
    • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

    ^ Inductances In an AC Circuit Inductance (L) is measured using the unit of 1 henry which is the inductance in when 1 volt is produced by a current changing at the rate of 1 ampere/second.
    • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

    ^ In such a case the magnet coils are connected alternately in both the circuits; that is 1, 3, 5 ....
    • A New System of Alternating Current Motors and Transformers - Wikisource 10 February 2010 11:011 UTC en.wikisource.org [Source type: Original source]

    Keelin, "Alternating current Tools". JC Physics, 2002.
  • Williams, Trip "Kingpin", "Understanding Alternating Current, Some more power concepts".
  • "Table of Voltage, Frequency, TV Broadcasting system, Radio Broadcasting, by Country".
  • Professor Mark Csele's tour of the 25 Hz Rankine generating station
  • 50/60 hertz information
  • AC circuits Animations and explanations of vector (phasor) representation of RLC circuits
  • Blalock, Thomas J., "The Frequency Changer Era: Interconnecting Systems of Varying Cycles". The history of various frequencies and interconversion schemes in the US at the beginning of the 20th century
  • (Italian) Generating an a.c voltage.Interactive.
  1. ^ http://www.ieee.org/web/aboutus/history_center/conferences/che2007/prog_comm.html

Study guide

Up to date as of January 14, 2010

From Wikiversity

.
City lights viewed in a motion blurred exposure.
^ Jump to: navigation , search City lights viewed in a motion blurred exposure.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

The AC blinking causes the lines to be dotted rather than continuous.
.An alternating current (AC) is an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant.^ Alternating Current ( AC ) motors use electricity instead of gasoline.
  • Alternating Current (AC) Motors – Web Listings 10 February 2010 11:011 UTC www.business.com [Source type: FILTERED WITH BAYES]

^ What is alternating current ac?
  • WikiAnswers - What is the difference between alternating current and direct current 10 February 2010 11:011 UTC wiki.answers.com [Source type: FILTERED WITH BAYES]

^ Where are alternating current and direct current?
  • WikiAnswers - What is the mathematical Formula for converting direct current to alternating current 10 February 2010 11:011 UTC wiki.answers.com [Source type: General]

.The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy.^ Average power in ac circuit is 0.5 I V cos f .

^ The waveform of an alternating current power circuit is a sine wave.
  • National High Magnetic Field Laboratory - Alternating Current Tutorial 10 February 2010 11:011 UTC www.magnet.fsu.edu [Source type: FILTERED WITH BAYES]

^ The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy.
  • Alternating current 10 February 2010 11:011 UTC www.cdxetextbook.com [Source type: FILTERED WITH BAYES]
  • Alternating Current - Appropedia: The sustainability wiki 10 February 2010 11:011 UTC www.appropedia.org [Source type: Reference]
  • Alternating current 10 February 2010 11:011 UTC moodle.student.cnwl.ac.uk [Source type: FILTERED WITH BAYES]

.However in certain applications different waveforms are used, such as triangular or square waves.^ However in certain applications different waveforms are used, such as triangular or square waves.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]
  • Alternating current 10 February 2010 11:011 UTC www.cdxetextbook.com [Source type: FILTERED WITH BAYES]
  • Alternating Current - Appropedia: The sustainability wiki 10 February 2010 11:011 UTC www.appropedia.org [Source type: Reference]
  • Alternating current 10 February 2010 11:011 UTC moodle.student.cnwl.ac.uk [Source type: FILTERED WITH BAYES]

^ Alternating current can generate several different types of wave forms: triangular, sine, or square waves.
  • What is Alternating Current - AC? - SuperTips by Superpages.com 10 February 2010 11:011 UTC www.superpages.com [Source type: General]

^ Some common types of waveforms associated with alternating currents when viewed using an oscilloscope will take the shape of a sinusoidal, square wave , or triangular and saw tooth wave pattern.
  • Glossary A 10 February 2010 11:011 UTC pcbwizards.com [Source type: Reference]

.Used generically, AC refers to the form in which electricity is delivered to businesses and residences.^ Electricity is commonly delivered to businesses and residences as alternating current.
  • Renewable Energy Glossary: View Basic Terms about Renewable Energy 10 February 2010 11:011 UTC www.tiogaenergy.com [Source type: FILTERED WITH BAYES]
  • Energy Finance Company - News & Links 10 February 2010 11:011 UTC www.energyfinancecompany.com [Source type: Reference]

^ Primarily used to power an electric generator.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ Used generically, AC refers to the form in which electricity is delivered to businesses and residences.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]
  • Alternating current 10 February 2010 11:011 UTC www.cdxetextbook.com [Source type: FILTERED WITH BAYES]
  • Alternating current 10 February 2010 11:011 UTC moodle.student.cnwl.ac.uk [Source type: FILTERED WITH BAYES]

.However, audio and radio signals carried on electrical wire are also examples of alternating current.^ However, audio and radio signals carried on electrical wire are also examples of alternating current.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • Alternating current 10 February 2010 11:011 UTC www.cdxetextbook.com [Source type: FILTERED WITH BAYES]
  • Alternating current 10 February 2010 11:011 UTC moodle.student.cnwl.ac.uk [Source type: FILTERED WITH BAYES]

^ The audio signal in a stereo system is seen as alternating current.
  • Cardas Audio 10 February 2010 11:011 UTC www.cardas.com [Source type: General]

^ Electric machinery -- Alternating current .
  • Browse subject: Electric machinery -- Alternating current | The Online Books Page 10 February 2010 11:011 UTC onlinebooks.library.upenn.edu [Source type: General]
  • Problems in Alternating Current Machinery, by Waldo V. Lyon | The Online Books Page 10 February 2010 11:011 UTC onlinebooks.library.upenn.edu [Source type: General]

.In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.^ In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.

^ In these applications, an important goal is often the recovery of information encoded (or modulated ) onto the AC signal.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Voltage signal conditioners and current signal conditioners amplify or modulate voltage or alternating current (AC) and/or direct current (DC) signals.

Contents

History

William Stanley, Jr. designed one of the first practical devices to transfer AC power efficiently between isolated circuits. .Using pairs of coils wound on a common iron core, his design, called an induction coil, was an early precursor of the modern transformer.^ His design was an early precursor of the modern transformer , called an induction coil.
  • Alternating current - Free Encyclopedia 10 February 2010 11:011 UTC www.wacklepedia.com [Source type: Reference]

^ Using pairs of coils wound on a common iron core, his design, called an induction coil , was an early precursor of the modern transformer .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ They are made of two or more separate coils of wire wrapped around a common core, normally made of laminated iron sheets.

.The system used today was devised in the late nineteenth century, largely by Nikola Tesla.^ The system used today was devised in the late nineteenth century, largely by Nikola Tesla .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ The power of light Even today many people do not know who Nikola Tesla is.
  • Alternating Current - Myblog V2 – Blog WordPress Theme 10 February 2010 11:011 UTC wordpress.youjoomla.net [Source type: General]

^ The system used today was devised by many contributors including Nikola Tesla , George Westinghouse , Lucien Gaulard , John Dixon Gibbs , and Oliver Shallenger from 1881 to 1889 .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.Contributions were also made by George Westinghouse, Lucien Gaulard, John Dixon Gibbs,Wilhelm Siemens and Oliver Shallenger.^ The system used today was devised by many contributors including Nikola Tesla , George Westinghouse , Lucien Gaulard , John Dixon Gibbs , and Oliver Shallenger from 1881 to 1889 .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Contributions were also made by George Westinghouse , Lucien Gaulard , John Dixon Gibbs , Wilhelm Siemens and Oliver Shallenger .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ T he case can be made that by the late 1800s George Westinghouse was America’s greatest living engineer.
  • "A Man for His People," Feature Article, October 2008 10 February 2010 11:011 UTC www.memagazine.org [Source type: FILTERED WITH BAYES]

.AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity efficiently over long distances.^ AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity efficiently over long distances.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Grid - The layout of an electrical distribution system.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

.The first modern commercial power plant using three-phase alternating current was at the Mill Creek hydroelectric plant near Redlands, California in 1893. Its designer was Almirian Decker, a brilliant young engineer.^ The first modern commercial power plant using three-phase alternating current was at the Mill Creek hydroelectric plant near Redlands, California in 1893.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Alternating current (a.c) is generated from alternating current generators such as hydroelectric power generators.
  • http://www.one-school.net/Malaysia/UniversityandCollege/SPM/revisioncard/physics/electromagnetism/alternatingcurrent.html 10 February 2010 11:011 UTC www.one-school.net [Source type: Academic]

^ Loss of all alternating current power.
  • 10 CFR 50.63 Loss of all alternating current power. 10 February 2010 11:011 UTC www.nrc.gov [Source type: FILTERED WITH BAYES]

.Decker's innovative design incorporated 10,000 volt three phase transmission and established the standards for the complete system of generation, transmission and motors used today.^ Three phase motors are self starting.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

^ Wye three-phase system.
  • Capacitor Definition of Terms - Capacitor Industries' Glossary 10 February 2010 11:011 UTC www.capacitorindustries.com [Source type: Reference]

^ These comprised a complete system of generators, transformers, transmission lines, motors and lighting.
  • PBS: Tesla - Master of Lightning: War of the Currents 10 February 2010 11:011 UTC www.pbs.org [Source type: FILTERED WITH BAYES]

.And through the use of alternating current, Charles Proteus Steinmetz of General Electric was able to solve many of the problems associated with electricity generation and transmission.^ Voltage regulator for alternating current generator .
  • Voltage regulator for alternating ... - Google Patent Search 10 February 2010 11:011 UTC www.google.com [Source type: News]

^ Electricity is generated in many ways.

^ Alternating current (AC) generators .
  • Generator - body, used, water, plants, energy, gas, basic, change, part, principle, Principle of operation, Alternating current (AC) generators 10 February 2010 11:011 UTC www.scienceclarified.com [Source type: FILTERED WITH BAYES]

.Alternating current circuit theory evolved rapidly in the latter part of the 19th and early 20th century.^ Chapter 21 - Alternating-Current Circuits .
  • Chapter 21 - Alternating-Current Circuits 10 February 2010 11:011 UTC www.mhhe.com [Source type: Reference]

^ Treatise on the theory of alternating currents,.

^ Alternating current circuit theory evolved rapidly in the latter part of the 19th and early 20th century.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Notable contributors to the theoretical basis of alternating current calculations include Charles Steinmetz, James Clerk Maxwell, Oliver Heaviside, and many others.^ Notable contributors to the theoretical basis of alternating current calculations include Charles Steinmetz, James Clerk Maxwell , Oliver Heaviside , and many others.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ The advantages of using alternating current are many.
  • alternating current@Everything2.com 10 February 2010 11:011 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ Includes the theory of alternating current and power.
  • PCC Catalog 10 February 2010 11:011 UTC www.pcc.edu [Source type: Reference]

Calculations in unbalanced three-phase systems were simplified by the symmetrical components methods discussed by Charles Legeyt Fortescue in 1918.

Transmission, distribution, and domestic power supply

Main article: Electricity distribution
.AC voltage can be stepped up or down by a transformer to a different voltage.^ The stepping up and stepping down of voltage is done on the AC grids.
  • HVDC -- 3DSoftware.com 10 February 2010 11:011 UTC www.3dsoftware.com [Source type: Reference]

^ Step-down transformer steps voltage down and current up.
  • What is alternating current (AC)? : BASIC AC THEORY 10 February 2010 11:011 UTC www.allaboutcircuits.com [Source type: FILTERED WITH BAYES]

^ Steps AC voltage up or down, depending on the application.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.Modern High-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power over long distances.^ Voltage regulator for alternating current generator .
  • Voltage regulator for alternating ... - Google Patent Search 10 February 2010 11:011 UTC www.google.com [Source type: News]

^ Where are alternating current and direct current?
  • WikiAnswers - What is the mathematical Formula for converting direct current to alternating current 10 February 2010 11:011 UTC wiki.answers.com [Source type: General]

^ Voltage regulator for direct current aircraft power bus .
  • Voltage regulator for alternating ... - Google Patent Search 10 February 2010 11:011 UTC www.google.com [Source type: News]

.However, these tend to be more expensive and less efficient than transformers, and did not exist when Edison, Westinghouse and Tesla were designing their power systems.^ However, these tend to be more expensive and less efficient than transformers, and did not exist when Edison , Westinghouse and Tesla were designing their power systems.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Isn't DC less efficient than AC power?

^ Power less than 24 Volts (i.e.

.Use of a higher voltage leads to significantly more efficient transmission of power.^ To get a higher frequency he needed more power.
  • History of Communications - RADIO: The Power that Made Radio Realistic 10 February 2010 11:011 UTC www.fcc.gov [Source type: FILTERED WITH BAYES]

^ It's efficient for power companies to transfer energy in bulk and at higher voltages.
  • Alternating Current (AC) vs. Direct Current (DC) and Electricity 10 February 2010 11:011 UTC www.dynowatt.com [Source type: FILTERED WITH BAYES]

^ Use of a higher voltage leads to more efficient transmission of power.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.The power losses in a conductor are a product of the square of the current and the resistance of the conductor, described by the formula  P=I^2 \cdot R \,\!</span><span class=^ Loss of all alternating current power.
  • 10 CFR 50.63 Loss of all alternating current power. 10 February 2010 11:011 UTC www.nrc.gov [Source type: FILTERED WITH BAYES]

^ So while the power carried in the circuit is proportional to its current, the loss of power is proportional to the square of its current.
  • Powering Our 21st Century Lives With a 19th Century Design — The Green Grok 10 February 2010 11:011 UTC www.nicholas.duke.edu [Source type: FILTERED WITH BAYES]
  • Our Grid: Powering Our 21st Century Lives With a 19th Century Design | Popular Science 10 February 2010 11:011 UTC www.popsci.com [Source type: General]

^ And I is squared in the power loss expression.
  • PHY 207 Chapter 34 Alternating Circuits / Dr. Miner 10 February 2010 11:011 UTC campus.udayton.edu [Source type: Academic]

." src="http://images-mediawiki-sites.thefullwiki.org/01/1/8/2/7964861879444369.png" />.^ See OPEC's site at http://www.opec.org for more information.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

.This means that when transmitting a fixed power on a given wire, if the current is doubled, the power loss will be four times greater.^ This means that when transmitting a fixed power on a given wire, if the current is doubled, the power loss will be four times greater.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC has at least four advantages over DC in a power distribution grid: 1.AC suffers from significantly less line loss than DC when transmitted over long distances because it is easy to step it up to extremely high voltages.
  • fUSION Anomaly. Alternating Current 10 February 2010 11:011 UTC fusionanomaly.net [Source type: FILTERED WITH BAYES]

^ On Earth, the electricity that comes from power plants is called alternating current , or AC. In the United States, this means that the direction of the ...
  • Results: alternating current 10 February 2010 11:011 UTC search.nasa.gov [Source type: Academic]

.Since the power transmitted is equal to the product of the current, the voltage and the cosine of the phase difference φ (P = IVcosφ), the same amount of power can be transmitted with a lower current by increasing the voltage.^ Power is equal to Volts x Amps, and so the average power produced will be equal to the averages of the products of the instantaneous voltages and currents.
  • Understanding Alternating Current 10 February 2010 11:011 UTC www.alpharubicon.com [Source type: FILTERED WITH BAYES]

^ The voltage across any resistor and the current through that resistor have the same phase angle.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ When voltage increases, current decreases in the same proportion, and vice-versa.

.Therefore it is advantageous when transmitting large amounts of power to distribute the power with high voltages (often hundreds of kilovolts).^ Therefore it is advantageous when transmitting large amounts of power to distribute the power with high voltages (often hundreds of kilovolts).
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC has at least four advantages over DC in a power distribution grid: 1.AC suffers from significantly less line loss than DC when transmitted over long distances because it is easy to step it up to extremely high voltages.
  • fUSION Anomaly. Alternating Current 10 February 2010 11:011 UTC fusionanomaly.net [Source type: FILTERED WITH BAYES]

^ So power companies convert alternating current to very high voltages for transmission (such as 1 million volts), then drop it back down to lower voltages for distribution (such as 1,000 volts), and finally down to 120 volts inside the house for safety.
  • HowStuffWorks "Direct Current vs. Alternating Current" 10 February 2010 11:011 UTC science.howstuffworks.com [Source type: FILTERED WITH BAYES]

.However, high voltages also have disadvantages, the main ones being the increased insulation required, and generally increased difficulty in their safe handling.^ However, high voltages also have disadvantages, the main ones being the increased insulation required, and generally increased difficulty in their safe handling.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Work safely with high voltage .
  • Work safely with high voltage 10 February 2010 11:011 UTC www.instructables.com [Source type: FILTERED WITH BAYES]

^ The safety problem of a transformer insulation breakdown applying high-voltage to the secondary was solved by the simple but effective expedient of grounding the transformer secondary winding.
  • Early Electrification of Buffalo: Advent of Alternating Current - GHN 10 February 2010 11:011 UTC www.ieeeghn.org [Source type: Reference]

.In a power plant, power is generated at a convenient voltage for the design of a generator, and then stepped up to a high voltage for transmission.^ In a power plant , power is generated at a convenient voltage for the design of a generator , and then stepped up to a high voltage for transmission.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The transformer "steps up" the voltage.

^ AC has at least four advantages over DC in a power distribution grid: 1.AC suffers from significantly less line loss than DC when transmitted over long distances because it is easy to step it up to extremely high voltages.
  • fUSION Anomaly. Alternating Current 10 February 2010 11:011 UTC fusionanomaly.net [Source type: FILTERED WITH BAYES]

.Near the loads, the transmission voltage is stepped down to the voltages used by equipment.^ The voltage can then be stepped down for use in buildings, street lights, and so forth.
  • Alternating Current | FHSST: FREE HIGH SCHOOL SCIENCE TEXTS 10 February 2010 11:011 UTC www.fhsst.org [Source type: FILTERED WITH BAYES]

^ Near the loads, the transmission voltage is stepped down to the voltages used by equipment.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Three Phase Full Wave Rectified Alternating Current Three phase current is often used to power industrial equipment because it has more favorable power transmission and line loading characteristics.
  • Magnetizing Current 10 February 2010 11:011 UTC www.ndt-ed.org [Source type: Reference]

.Consumer voltages vary depending on the country and size of load, but generally motors and lighting are built to use up to a few hundred volts between phases.^ I don't use low voltage lighting.

^ Consumer voltages vary depending on the country and size of load, but generally motors and lighting are built to use up to a few hundred volts between phases.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For a sinusoidal voltage: V rms is useful in calculating the power consumed by a load.
  • Alternating current - Free Encyclopedia 10 February 2010 11:011 UTC www.wacklepedia.com [Source type: Reference]

.The utilization voltage delivered to equipment such as lighting and motor loads is standardized, with an allowable range of voltage over which equipment is expected to operate.^ The utilization voltage delivered to equipment such as lighting and motor loads is standardized, with an allowable range of voltage over which equipment is expected to operate.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Certain types of loads (e.g., lamps, motors) will draw a larger initial current because their impedance is lower at startup than during steady state operation.

^ Other parts of the world use different voltages ranging from 100VAC to 240VAC, and of course, heavy equipment anywhere can use much higher voltages.
  • Direct and Alternating Current 10 February 2010 11:011 UTC www.pcguide.com [Source type: FILTERED WITH BAYES]

.Standard power utilization voltages and percentage tolerance vary in the different mains power systems found in the world.^ Standard power utilization voltages and percentage tolerance vary in the different mains power systems found in the world.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Hz power (one third of the mains frequency) is still used in some European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Power attained in an AC circuit as a product of effective voltage and current which reach their peak at different times.
  • Learn Electronics Lessons and Information Pages 10 February 2010 11:011 UTC www.twysted-pair.com [Source type: Reference]

.Three-phase electrical generation is very common.^ Three-phase electrical generation is very common.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Three-phase electrical generation is very common and is a more efficient use of conductors.
  • Alternating current - Free Encyclopedia 10 February 2010 11:011 UTC www.wacklepedia.com [Source type: Reference]

^ The focus is on electrical theory for single-phase AC circuits, including: AC voltage generation and terminology inductance and inductive reactance capacitance and capacitive reactance power relationships series RLC circuits parallel RLC circuits introduction to three-phase power systems Hours: 60 .
  • NAIT | Alternating Current Fundamentals - ELT120W 10 February 2010 11:011 UTC www.nait.ca [Source type: News]

.Three separate coils in the generator stator are physically offset by an angle of 120° to each other.^ Three separate coils in the generator stator are physically offset by an angle of 120° to each other.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The same thing happens with a DC generator, where the motion of coiled wire through a magnetic field pushes electrons out of one terminal and attracts electrons to the other terminal.
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]
  • AC Electricity - Alternating Current Power Explained 10 February 2010 11:011 UTC www.electricityforum.com [Source type: Reference]

^ The winding is also insulated from the frame.  The motor stator winding is identical to a generator armature that has a like amount of poles.  Each winding is overlapped and is electrically and mechanically 120 degrees out of phase.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: Reference]

.Three current waveforms are produced that are equal in magnitude and 120° out of phase to each other.^ Three current waveforms are produced that are equal in magnitude and 120° out of phase to each other.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ A type of AC power that is generated with three waveforms that are not in phase with each other.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ But why are the current and voltage out of phase with each other?
  • Understanding Alternating Current 10 February 2010 11:011 UTC www.alpharubicon.com [Source type: FILTERED WITH BAYES]

.If the load on a three-phase system is balanced equally between the phases, no current flows through the neutral point.^ Wye three-phase system.
  • Capacitor Definition of Terms - Capacitor Industries' Glossary 10 February 2010 11:011 UTC www.capacitorindustries.com [Source type: Reference]

^ The neutral current is zero with equal loads on both generators.
  • Early Electrification of Buffalo: Advent of Alternating Current - GHN 10 February 2010 11:011 UTC www.ieeeghn.org [Source type: Reference]

^ A balanced connection is a three-wire system.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

.Even in the worst-case unbalanced (linear) load, the neutral current will not exceed the highest of the phase currents.^ Even in the worst-case unbalanced (linear) load, the neutral current will not exceed the highest of the phase currents.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Since voltage and current may not be in phase on AC systems, the apparent power thus calculated may not equal the real power, but may actually exceed it.
  • 'A' - Glossary of Energy Terms - MicroPlanet Energy Technology 10 February 2010 11:011 UTC www.microplanet.com [Source type: Academic]

^ Even after eliminating the cases where current is used to mean contemporary, there seem to be a plenitude of examples.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

.For three-phase at low (normal mains) voltages a four-wire system is normally used.^ Wye three-phase system.
  • Capacitor Definition of Terms - Capacitor Industries' Glossary 10 February 2010 11:011 UTC www.capacitorindustries.com [Source type: Reference]

^ I don't use low voltage lighting.

^ A balanced connection is a three-wire system.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

.When stepping down three-phase, a transformer with a Delta primary and a Star secondary is often used so there is no need for a neutral on the supply side.^ When stepping down three-phase, a transformer with a Delta primary and a Star secondary is often used so there is no need for a neutral on the supply side.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Delta Wye The method of connection for both primary and secondary windings of a three-phase transformer bank.

^ Delta Connection A method used for connecting the three windings of a three-phase transformer (or three single-phase transformers).

.For smaller customers (just how small varies by country and age of the installation) only a single phase and the neutral or two phases and the neutral are taken to the property.^ For smaller customers (just how small varies by country and age of the installation) only a single phase and the neutral or two phases and the neutral are taken to the property.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ In 1966 Mr. Colin Johnstone, owner of Johnstone Mfg., needed to run some three phase machines but only had single phase power available.
  • Alternating Current AC Supplies Wholesale Directory 10 February 2010 11:011 UTC www.battery4sale.com [Source type: General]

^ Three-wire single phase systems, with a single centre-tapped transformer giving two live conductors, is a common distribution scheme for residential and small commercial buildings in North America.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.For larger installations all three phases and the neutral are taken to the main distribution panel.^ One circuit is the three-phase  power circuit supplied from the distribution power panel.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: FILTERED WITH BAYES]

^ For larger installations all three phases and the neutral are taken to the main distribution panel.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ When stepping down three-phase, a transformer with a Delta primary and a Star secondary is often used so there is no need for a neutral on the supply side.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.From the three-phase main panel, both single and three-phase circuits may lead off.^ One circuit is the three-phase  power circuit supplied from the distribution power panel.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: FILTERED WITH BAYES]

^ From the three-phase main panel, both single and three-phase circuits may lead off.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The focus is on electrical theory for single-phase AC circuits, including: AC voltage generation and terminology inductance and inductive reactance capacitance and capacitive reactance power relationships series RLC circuits parallel RLC circuits introduction to three-phase power systems Hours: 60 .
  • NAIT | Alternating Current Fundamentals - ELT120W 10 February 2010 11:011 UTC www.nait.ca [Source type: News]

.Three-wire single phase systems, with a single centre-tapped transformer giving two live conductors, is a common distribution scheme for residential and small commercial buildings in North America.^ Wye three-phase system.
  • Capacitor Definition of Terms - Capacitor Industries' Glossary 10 February 2010 11:011 UTC www.capacitorindustries.com [Source type: Reference]

^ A residential photovoltaic system is a distributed system.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ A balanced connection is a three-wire system.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

.This arrangement is sometimes incorrectly referred to as "two phase". A similar method is used for a different reason on construction sites in the UK. Small power tools and lighting are supposed to be supplied by a local center-tapped transformer with a voltage of 55V between each power conductor and the earth.^ The relationship between voltage and power is: .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Banked Two or more single-phase transformers connected together, or banked, to supply power.

^ This arrangement is sometimes incorrectly referred to as "two phase".
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.This significantly reduces the risk of electric shock in the event that one of the live conductors becomes exposed through an equipment fault whilst still allowing a reasonable voltage for running the tools.^ This significantly reduces the risk of electric shock in the event that one of the live conductors becomes exposed through an equipment fault whilst still allowing a reasonable voltage for running the tools.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Explain risks involving electrical shock.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ This conductor provides protection from electrical shock due to accidental contact of circuit conductors with the case of portable appliances and tools.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.A third wire, called the bond wire, is often connected between non-current carrying metal enclosures and earth ground.^ A third wire is often connected between non-current carrying metal enclosures and earth ground.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ A third wire , called the bond wire, is often connected between non-current carrying metal enclosures and earth ground.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Live Wire The wire connected to the charger power terminal which carries the current.
  • Glossary of Electric Fencing Terms | FiShock™ 10 February 2010 11:011 UTC www.fishock.com [Source type: General]

.This conductor provides protection from electrical shock due to accidental contact of circuit conductors with the metal chassis of portable appliances and tools.^ This conductor provides protection from electrical shock due to accidental contact of circuit conductors with the metal chassis of portable appliances and tools.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ This conductor provides protection from electrical shock due to accidental contact of circuit conductors with the case of portable appliances and tools.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ A conductor that directs electricity in a circuit.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.Bonding all non-current carrying metal parts into one complete system ensures there is always a low impedance path to ground sufficient to carry any fault current for as long as it takes for the system to clear the fault.^ Bonding all non-current carrying metal parts into one complete system ensures there is always a low impedance path to ground sufficient to carry any fault current for as long as it takes for the system to clear the fault.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ This low impedance path allows the maximum amount of fault current to flow, causing the overcurrent protection device (Breakers, fuses) to trip or burn out as quickly as possible, returning the electrical system to a safe state.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ RMS Line Current - The square root of the average of the squares of all the instantaneous current amplitudes occurring during one cycle.
  • Bristol International Inc, Electrical and Communications Contractor, Toronto, Mississauga 10 February 2010 11:011 UTC bristolinc.com [Source type: Academic]

.This low impedance path allows the maximum amount of fault current to flow, causing the overcurrent protection device (Breakers, fuses) to trip or burn out as quickly as possible, returning the electrical system to a safe state.^ This low impedance path allows the maximum amount of fault current to flow, causing the overcurrent protection device (Breakers, fuses) to trip or burn out as quickly as possible, returning the electrical system to a safe state.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ An electric field will not cause harm without a current > > path.
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]
  • Animal cruelty - talk.origins | Google Groups 10 February 2010 11:011 UTC groups.google.com [Source type: FILTERED WITH BAYES]

^ The positive terminal of an electric current flow.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.All bond wires are bonded to ground at the main service panel, as is the Neutral/Identified Conductor if present.^ All bond wires are bonded to ground at the main service panel, as is the Neutral/Identified Conductor if present.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ This text gets to the root of all problems associated with grounding and bonding.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

^ Based on the 2008 NEC , this hands-on guide illustrates Code provisions concerning circuit and system grounding; grounding electrode systems and electrode conductors; enclosure, raceway, and service cabling grounding; bonding; equipment grounding and equipment grounding conductors; and much more...
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

AC power supply frequencies

.The frequency of the electrical system varies by country; most electric power is generated at either 50 or 60 Hz.^ The frequency of the electrical system varies by country.
  • WikiAnswers - What is the difference between alternating current and direct current 10 February 2010 11:011 UTC wiki.answers.com [Source type: FILTERED WITH BAYES]

^ Most electric power is generated at either 50 or 60 Hertz (cycles per second).
  • WikiAnswers - What is the difference between alternating current and direct current 10 February 2010 11:011 UTC wiki.answers.com [Source type: FILTERED WITH BAYES]

^ The frequency of the electrical system varies by country; most electric power is generated at either 50 or 60 Hz.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.See List of countries with mains power plugs, voltages and frequencies.^ See List of countries with mains power plugs, voltages and frequencies .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ High-voltage circuit breakers are most frequently installed in outdoor switchyards, used in utility transmission and distribution substations, and in large industrial power substations.
  • NEMA Publishes SG 4-2009, 'Alternating Current High-Voltage Circuit Breakers' 10 February 2010 11:011 UTC ecmweb.com [Source type: General]

^ Hz power (one third of the mains frequency) is still used in some European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Some countries have a mixture of 50 Hz and 60 Hz supplies, notably Japan.^ Some countries have a mixture of 50 Hz and 60 Hz supplies, notably Japan.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ It changes direction at a specific frequency-- 60 times per second, or 60 Hz (in the United States, Japan, and a couple of other countries; in Europe the standard is 50 Hz).
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

^ The back-and-forth motion occurs between 50 and 60 times per second, depending on the electrical system of the country.
  • AC Electricity - Alternating Current Power Explained 10 February 2010 11:011 UTC www.electricityforum.com [Source type: Reference]

.A low frequency eases the design of low speed electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways, but also causes a noticeable flicker in incandescent lighting and objectionable flicker of fluorescent lamps.^ A low frequency eases the design of low speed electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways , but also causes a noticeable flicker in incandescent lighting and objectionable flicker of fluorescent lamps .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ AC generators are simple, cheaper and more reliable than DC generators AC can readily be switched by circuit breakers at any voltage, whereas DC can only be switched at low voltages AC motors and other electrical appliances are cheaper, simpler, and more reliable than those designed to work with DC The frequency can be very precisely controlled and so AC is useful in motors that require accurate speed eg.
  • Alternating Current vs. Direct Current - Open Source Tesla | 10 February 2010 11:011 UTC www.think-aboutit.com [Source type: FILTERED WITH BAYES]

^ AC electric motors now have options and configurations to suit almost any application.If you have determined that an AC motor control is what your design needs, now you just need to find the supplier that carries the AC motor that ...
  • Alternating Current (AC) Motors Information | Business.com 10 February 2010 11:011 UTC www.business.com [Source type: General]
  • Alternating Current (AC) Motors – Web Listings 10 February 2010 11:011 UTC www.business.com [Source type: FILTERED WITH BAYES]

.16⅔ Hz power (one third of the mains frequency) is still used in some European rail systems, such as in Austria, Germany, Norway, Sweden and Switzerland.^ European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Hz power (one third of the mains frequency) is still used in some European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Low frequencies, such as 50 and 60 cycles per second ( hertz ), are used for domestic and commercial power, but alternating currents of frequencies around 100,000,000 cycles per second (100 megahertz) are used in television and of several thousand megahertz in radar or microwave communication .
  • alternating current (electronics) -- Britannica Online Encyclopedia 10 February 2010 11:011 UTC www.britannica.com [Source type: Reference]

.The use of lower frequencies also provided the advantage of lower impedance losses, which are proportional to frequency.^ The use of lower frequencies also provided the advantage of lower impedance losses, which are proportional to frequency.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Compute the frequency of a source of voltage V which would give the maximum current when applied to the circuit of the Impedance Apparatus used.
  • Alternating Current Series Circut 10 February 2010 11:011 UTC www.stkate.edu [Source type: Academic]

^ Tissues have a lower impedance to middle frequency vs. (Fig.
  • Electric Sympathetic Block, High Frequency Electric, Pharmacologic Nerve Block, Electroporation, Relief for Sympathetic Pain 10 February 2010 11:011 UTC wehelpwhathurts.homestead.com [Source type: Academic]

.It was this argument that resulted in the use of 25 Hz in the initial generation installations at Niagara Falls, in anticipation of long-distance transmission to Toronto.^ It was this argument that resulted in the use of 25 Hz in the initial generation installations at Niagara Falls , in anticipation of long-distance transmission to Toronto .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ The latter case may serve as a reminder that hydroelectric power, using a fall of water to drive water turbines, has been developed to generate electricity where the climate and topography make it possible to combine production with convenient transmission to a market.
  • Alternating Current vs. Direct Current - Open Source Tesla | 10 February 2010 11:011 UTC www.think-aboutit.com [Source type: FILTERED WITH BAYES]

^ In Europe (and a few other countries) they use DC current, which is far less effective at delivering power over long distances.
  • The television set in your living room runs on _____current.? - Yahoo! Answers 10 February 2010 11:011 UTC answers.yahoo.com [Source type: General]

.Improvements in transmission technology later made it feasible to use 60 Hz as an acceptable, and more desirable, frequency.^ Improvements in transmission technology later made it feasible to use 60 Hz as an acceptable, and more desirable, frequency.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ In American uses of alternating current the voltage on a line from the power company is a sinusoid with a frequency of 60 Hz and an amplitude of a 140 volts ; it has an RMS value of 120 volts.
  • alternating current@Everything2.com 10 February 2010 11:011 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ It was this argument that resulted in the use of 25 Hz in the initial generation installations at Niagara Falls , in anticipation of long-distance transmission to Toronto .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.The conversion lasted into the 1950s, costing Ontario Hydro dearly as it replaced all clocks, refrigerators and other motor-driven appliances in the Toronto area.^ The conversion lasted into the 1950s, costing Ontario Hydro dearly as it replaced all clocks, refrigerators and other motor-driven appliances in the Toronto area.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ As the innovators in all our business areas, we are constantly driven to provide high quality, state-of-the-art products, which improve our customers efficiency, cut their production costs, and, at the same time respect the environment.
  • 50 to 250 kVA Alternating Current (AC) Generator Sets - US (United States) - Suppliers of 50 to 250 kVA Alternating Current (AC) Generator Sets on Kellysearch 10 February 2010 11:011 UTC www.kellysearch.com [Source type: Reference]

^ (BOS)--Represents all components and costs other than the PV modules.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

.Off-shore, textile industry, marine, computer mainframe, aircraft, and spacecraft applications sometimes use 400 Hz, for benefits of reduced weight of apparatus or higher motor speeds.^ Off-shore, textile industry, marine, computer mainframe , aircraft, and spacecraft applications sometimes use 400 Hz, for benefits of reduced weight of apparatus or higher motor speeds.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ When used for higher duties the starter controls include methods of reducing the voltage at start-up.
  • Alternating Current Notes 10 February 2010 11:011 UTC www.roymech.co.uk [Source type: Academic]

^ This drawback is overshadowed by the fact that sensory perception are reduced at higher frequencies, both current tissue penetration and usable intensity can be increased as the frequency used is increased [1,2,29].
  • Electric Sympathetic Block, High Frequency Electric, Pharmacologic Nerve Block, Electroporation, Relief for Sympathetic Pain 10 February 2010 11:011 UTC wehelpwhathurts.homestead.com [Source type: Academic]

Effects at high frequencies

.A direct, constant, current flows uniformly throughout the cross-section of the (uniform) wire that carries it.^ Current that regularly reverses the direction of its flow.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ The direction of direct current remains constant.
  • WikiAnswers - What is the difference between alternating current and direct current 10 February 2010 11:011 UTC wiki.answers.com [Source type: FILTERED WITH BAYES]

^ The current alternates in direction within the wire .
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]

.With alternating current of any frequency, the current is forced towards the outer surface of the wire, and away from the center.^ With alternating current of any frequency, the current is forced towards the outer surface of the wire, and away from the center.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The current alternates in direction within the wire .
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]

^ The most common frequency of alternating current is 60 cycles per second (usually termed 60 cycles) or more commonly, 60 Hertz (Hz).
  • The Basics of Alternating Current 10 February 2010 11:011 UTC ecmweb.com [Source type: General]

.This is due to the fact that an electric charge which accelerates (as is the case of an alternating current) radiates electromagnetic waves, and materials of high conductivity (the metal which makes up the wire) do not allow propagation of electromagnetic waves.^ Any material that has a limited capacity for conducting an electric current.
  • Big Frog Mountain- Solar Electric Glossary Of Terminology Used In Renewable Or Alternative Energy Systems 10 February 2010 11:011 UTC bigfrogmountain.com [Source type: Reference]

^ Electromagnetic Waves - Radiation that consists of traveling waves of electric and magnetic disturbances.
  • EIA Energy Kids - Glossary 10 February 2010 11:011 UTC tonto.eia.doe.gov [Source type: Reference]

^ A neutral wire is necessary to allow the currents to return to the alternator.
  • WikiAnswers - What is the difference between alternating current and direct current 10 February 2010 11:011 UTC wiki.answers.com [Source type: FILTERED WITH BAYES]

.This phenomenon is called skin effect.^ This phenomenon is called skin effect .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to skin effect ohmic heating (also called I 2 R loss).
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths.^ At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ The skin depth is the thickness at which the current density is reduced by 63%.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ For such frequencies, the concepts of voltages and currents are no longer used.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.The skin depth is the thickness at which the current density is reduced by 63%.^ The skin depth is the thickness at which the current density is reduced by 63%.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For example, the skin depth of a copper conductor is approximately 8.57mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Even at relatively low frequencies used for high power transmission (50–60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors.^ Next Patent (Low frequency high o...
  • Alternating current generator - Patent 4117388 10 February 2010 11:011 UTC www.freepatentsonline.com [Source type: Reference]

^ The frequency for the household current in the US is 60 Hz.

^ Even at relatively low frequencies used for high power transmission (50–60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.^ The skin depth is the thickness at which the current density is reduced by 63%.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For example, the skin depth of a copper conductor is approximately 8.57mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.^ This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Care must be taken that the secondary of a current transformer is not disconnected from its load while current is flowing in the primary, as the transformer secondary will attempt to continue driving current across the effectively infinite impedance .
  • CR4 - Thread: Non-Contact Sensing for Voltage and Current 10 February 2010 11:011 UTC cr4.globalspec.com [Source type: FILTERED WITH BAYES]

.This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows.^ This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Resistance to current flow in an AC circuit.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to ohmic heating (also called I2R loss).^ The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to skin effect ohmic heating (also called I 2 R loss).
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to ohmic heating (also called I 2 R loss).
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ What is special about AC electricity is that the voltage can be readily changed, thus making it more suitable for long-distance transmission than DC electricity.
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]

Techniques for reducing AC resistance

.For low to medium frequencies, conductors can be divided into stranded wires, each insulated from one other, and the individual strands specially arranged to change their relative position within the conductor bundle.^ For low to medium frequencies, conductors can be divided into stranded wires, each insulated from one other, and the individual strands specially arranged to change their relative position within the conductor bundle.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The level of harmonic content can be very small and the wave-shape changes are often not detectable without the use of test equipment to determine the relative level of the harmonic frequency components.
  • Alternating Current 10 February 2010 11:011 UTC www.nzart.org.nz [Source type: FILTERED WITH BAYES]

^ If one value changes, the other must change to maintain the same ratio.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

.Wire constructed using this technique is called Litz wire.^ Wire constructed using this technique is called Litz wire .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Airtight Drywall Approach (ADA) - A building construction technique used to create a continuous air retarder that uses the drywall, gaskets, and caulking.

.This measure helps to partially mitigate skin effect by forcing more equal current flow throughout the total cross section of the stranded conductors.^ Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ This measure helps to partially mitigate skin effect by forcing more equal current flow throughout the total cross section of the stranded conductors.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ (Power is equal to the product of the applied voltage and the resulting current: P = I × E.) But those overhead wires are not perfect conductors; they exhibit some resistance.
  • What is Alternating Current? 10 February 2010 11:011 UTC www.play-hookey.com [Source type: FILTERED WITH BAYES]

.Litz wire is used for making high Q inductors, reducing losses in flexible conductors carrying very high currents at power frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers.^ Load : The electrical devices that use power.

^ Litz wire is used for making high Q inductors , reducing losses in flexible conductors carrying very high currents at power frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ At low frequencies, this loss is negligible, but is very noticeable at higher radio frequencies.

Techniques for reducing radiation loss

.As written above, an alternating current is made of electric charge under periodic acceleration, which causes radiation of electromagnetic waves.^ As written above, an alternating current is made of electric charge under periodic acceleration , which causes radiation of electromagnetic waves .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ In AC electricity, the current alternates in direction.
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]

^ AC circuits, alternating current electricity .
  • AC circuits, alternating current electricity 10 February 2010 11:011 UTC www.physclips.unsw.edu.au [Source type: FILTERED WITH BAYES]

.Energy that is radiated represents a loss.^ Energy that is radiated represents a loss.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.Depending on the frequency, different techniques are used to minimize the loss due to radiation.^ Techniques for reducing radiation loss .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Depending on the frequency, different techniques are used to minimize the loss due to radiation.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The effective emissivity is a different average of the same frequency-dependent absorptivity (the same as the frequency-dependent emissivity).
  • SBF Glossary: AK to ALVMA 10 February 2010 11:011 UTC www.plexoft.com [Source type: FILTERED WITH BAYES]

Twisted pairs

.At frequencies up to about 1 GHz, wires are paired together in cabling to form a twisted pair in order to reduce losses due to electromagnetic radiation and inductive coupling.^ Coaxial cables have acceptably small losses for frequencies up to about 20 GHz.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Techniques for reducing radiation loss .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ At frequencies up to about 1 GHz, wires are paired together in cabling to form a twisted pair in order to reduce losses due to electromagnetic radiation and inductive coupling .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.A twisted pair must be used with a balanced signalling system, where the two wires carry equal but opposite currents.^ A balanced connection is a three-wire system.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

^ A twisted pair must be used with a balanced signalling system, where the two wires carry equal but opposite currents.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ An unbalanced connection is a two-wire system.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

.The result is that each wire in the twisted pair radiates a signal that is effectively cancelled by the other wire, resulting in almost no electromagnetic radiation.^ The result is that each wire in the twisted pair radiates a signal that is effectively cancelled by the other wire, resulting in almost no electromagnetic radiation.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Any induced noise will appear at the input of the equipment-- there is no signal by which it can be canceled out.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

^ WIRED: Your alternating-current technology revolutionized electric power almost overnight, but the world is only now catching up with your other ideas.
  • Wired 6.10: Electric Mind 10 February 2010 11:011 UTC www.wired.com [Source type: General]

Coaxial cables

.At frequencies above 1 GHz, unshielded wires of practical dimensions lose too much energy to radiation, so coaxial cables are used instead.^ At frequencies above 1 GHz, unshielded wires of practical dimensions lose too much energy to radiation, so coaxial cables are used instead.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ A coaxial cable has a conductive wire inside a conductive tube.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Coaxial cables have acceptably small losses for frequencies up to about 20 GHz.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.A coaxial cable has a conductive wire inside a conductive tube.^ A coaxial cable has a conductive wire inside a conductive tube.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Cable shields either consist of a braid made of bare copper wires (shield braid, braid density = 80 percent), copper wires with counter helixes, copper bands or conductive plastic layers .
  • Dictionary 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]
  • Словарь 10 February 2010 11:011 UTC www.ebv.com [Source type: Reference]

^ At frequencies above 1 GHz, unshielded wires of practical dimensions lose too much energy to radiation, so coaxial cables are used instead.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.The current flowing on the inner conductor is equal and opposite to the current flowing on the inner surface of the outer tube.^ The current flowing on the inner conductor is equal and opposite to the current flowing on the inner surface of the outer tube.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ The opposition to current flow.
  • What is the definition of alternating current? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ (Power is equal to the product of the applied voltage and the resulting current: P = I × E.) But those overhead wires are not perfect conductors; they exhibit some resistance.
  • What is Alternating Current? 10 February 2010 11:011 UTC www.play-hookey.com [Source type: FILTERED WITH BAYES]

.This causes the electromagnetic field to be completely contained within the tube, and (ideally) no energy is radiated or coupled outside the tube.^ This causes the electromagnetic field to be completely contained within the tube, and (ideally) no energy is radiated or coupled outside the tube.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ As written above, an alternating current is made of electric charge under periodic acceleration , which causes radiation of electromagnetic waves .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Every electric circuit must have a voltage source, which acts as the source of energy for maintaining a voltage that causes current in a complete circuit.
  • Voltage Sources and Electric Current 10 February 2010 11:011 UTC facstaff.gpc.edu [Source type: Reference]

.Coaxial cables have acceptably small losses for frequencies up to about 20 GHz.^ Coaxial cables have acceptably small losses for frequencies up to about 20 GHz.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ At frequencies up to about 1 GHz, wires are paired together in cabling to form a twisted pair in order to reduce losses due to electromagnetic radiation and inductive coupling .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ At frequencies above 1 GHz, unshielded wires of practical dimensions lose too much energy to radiation, so coaxial cables are used instead.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.For microwave frequencies greater than 20 GHz, the dielectric losses (due mainly to the dissipation factor of the dielectric layer which separates the inner wire from the outer tube) become too large, making waveguides a more efficient medium for transmitting energy.^ Dissipation Factor varies with frequency and temperature.
  • Capacitor Definition of Terms - Capacitor Industries' Glossary 10 February 2010 11:011 UTC www.capacitorindustries.com [Source type: Reference]

^ For microwave frequencies greater than 20 GHz, the dielectric losses (due mainly to the dissipation factor of the dielectric layer which separates the inner wire from the outer tube) become too large, making waveguides a more efficient medium for transmitting energy.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ At frequencies greater than 200 GHz, waveguide dimensions become impractically too small, and the ohmic losses in the waveguide walls become large.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

Waveguides

.Waveguides are similar to coax cables, as both consist of tubes, with the biggest difference being that the waveguide has no inner conductor.^ Waveguides are similar to coax cables, as both consist of tubes, with the biggest difference being that the waveguide has no inner conductor.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ In a cable such as this, the phase conductor is surrounded by a pressure-resistant tube which is used as the casing conductor.
  • Electrical Energy Transmission Device - Patent application - has phase conductors which carry alternating current and have transfer impedance 10 February 2010 11:011 UTC www.faqs.org [Source type: Reference]

^ A shield is a wrap of a conductive metal covering the inner conductors of a given cable.
  • Some Basic Electricity 10 February 2010 11:011 UTC harada-sound.com [Source type: FILTERED WITH BAYES]

Waveguides can have any arbitrary cross section, but rectangular cross section are the most common. .With waveguides, the energy is no longer carried by an electric current, but by a guided electromagnetic field.^ With waveguides, the energy is no longer carried by an electric current , but by a guided electromagnetic field .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ But these charges cannot be used as a source of electric power, because they have no RESERVE of ENERGY to call upon to keep the electrons flowing.
  • Introduction to Radio Equipment - Chapter 7 10 February 2010 11:011 UTC www.hnsa.org [Source type: FILTERED WITH BAYES]

^ At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

.Waveguides have dimensions comparable to the wavelength of the alternating current to be transmitted, so are only feasible at microwave frequencies.^ Waveguides have dimensions comparable to the wavelength of the alternating current to be transmitted, so are only feasible at microwave frequencies.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ What frequency is the alternating current in the US? What is alternating current?
  • alternating current Facts, information, pictures | Encyclopedia.com articles about alternating current 10 February 2010 11:011 UTC www.encyclopedia.com [Source type: Academic]

^ By the alternate currents of the source only.
  • "A New System of Alternate Current Motors and Transformers" byNikola Tesla 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: FILTERED WITH BAYES]
  • A New System of Alternating Current Motors and Transformers - Wikisource 10 February 2010 11:011 UTC en.wikisource.org [Source type: Original source]
  • Library:A New System of Alternating Current Motors and Transformers - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: FILTERED WITH BAYES]

Fiber optics

.At frequencies greater than 200 GHz, waveguide dimensions become impractically too small, and the ohmic losses in the waveguide walls become large.^ At frequencies greater than 200 GHz, waveguide dimensions become impractically too small, and the ohmic losses in the waveguide walls become large.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ For microwave frequencies greater than 20 GHz, the dielectric losses (due mainly to the dissipation factor of the dielectric layer which separates the inner wire from the outer tube) become too large, making waveguides a more efficient medium for transmitting energy.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Waveguides have dimensions comparable to the wavelength of the alternating current to be transmitted, so are only feasible at microwave frequencies.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.Instead, fiber optics, which are a form of dielectric waveguides, can be used.^ Instead, fiber optics , which are a form of dielectric waveguides, can be used.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Optical fibers are bundled into groups to form fiber optic cable.
  • What is the definition of diode alternating current switch? 10 February 2010 11:011 UTC www.toolingu.com [Source type: Reference]

^ Instead of using four wires, with like result, three wires may be used, one forming a common return for both circuits.
  • "A New System of Alternate Current Motors and Transformers" byNikola Tesla 10 February 2010 11:011 UTC www.tfcbooks.com [Source type: FILTERED WITH BAYES]
  • A New System of Alternating Current Motors and Transformers - Wikisource 10 February 2010 11:011 UTC en.wikisource.org [Source type: Original source]
  • Library:A New System of Alternating Current Motors and Transformers - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: FILTERED WITH BAYES]

.For such frequencies, the concepts of voltages and currents are no longer used.^ As such, the comparison above is no longer applicable.
  • The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating Current Intertie, and Information on the Path 15 Transmission Upgrade-Rate Order No. WAPA-115 | Federal Register Environmental Documents | USEPA 10 February 2010 11:011 UTC www.epa.gov [Source type: General]

^ For such frequencies, the concepts of voltages and currents are no longer used.
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Hz power (one third of the mains frequency) is still used in some European rail systems, such as in Austria , Germany , Norway , Sweden and Switzerland .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

Mathematics of AC voltages

.
A sine wave, over one cycle (360°).
^ Recalling that one complete cycle of a sine wave is generated when a generator's rotor rotates through an angle of 360° (a full rotation), here's another way of plotting a sine wave: Here we're plotting voltage on the vertical axis, just as before, but now we're plotting degrees of the rotor's rotation on the horizontal axis.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ {Cycle} If we were to follow the changing voltage produced by a coil in an alternator from any point on the sine wave graph to that point when the wave shape begins to repeat itself, we would have marked exactly one \textit{cycle} of that wave.
  • Alternating Current | FHSST: FREE HIGH SCHOOL SCIENCE TEXTS 10 February 2010 11:011 UTC www.fhsst.org [Source type: FILTERED WITH BAYES]

^ The graph of current against time for one cycle or period T is the typical sine curve of Fig.
  • Alternating Current Series Circut 10 February 2010 11:011 UTC www.stkate.edu [Source type: Academic]

The dashed line represents the root mean square (RMS) value
.Alternating currents are accompanied by alternating voltages.^ Alternating currents are accompanied by alternating voltages.
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Because of this periodic motion of the electrons, the voltage and current follow a sine waveform, alternating between positive (+) and negative (−), as measured with a voltmeter or multimeter.
  • Alternating Current (AC) Electricity - Succeed in Understanding Physics: School for Champions 10 February 2010 11:011 UTC www.school-for-champions.com [Source type: Reference]

^ Alternator Rating Alternators are rated according to: Frequency Voltage Current kVA The frequency dictates the RPM (3000, 1500, etc).
  • Alternating Current Machines-Synchronous Machines 10 February 2010 11:011 UTC www.slideshare.net [Source type: Reference]

An AC voltage v can be described mathematically as a function of time by the following equation:
v(t)=V_\mathrm{peak}\cdot\sin(\omega t),
where
  • \displaystyle V_{\rm peak} is the peak voltage (unit: volt),
  • \displaystyle \omega is the angular frequency (unit: radians per second)
    • The angular frequency is related to the physical frequency, \displaystyle f, which represents the number of oscillations per second (unit = hertz), by the equation \omega = 2\,\pi\, f.
  • \displaystyle t is the time (unit: second).
.The peak-to-peak value of an AC voltage is defined as the difference between its positive peak and its negative peak.^ What is the difference between ac and dc currents?
  • Voltage Sources and Electric Current 10 February 2010 11:011 UTC facstaff.gpc.edu [Source type: Reference]

^ Maximum or peak value of the voltage, in volts (V) .
  • Principles of alternating current 10 February 2010 11:011 UTC www.tina.com [Source type: Academic]

^ The peak-to-peak value is the difference between a waveform's positive peak value and its negative peak value.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

.Since the maximum value of \displaystyle \sin(x) is +1 and the minimum value is −1, an AC voltage swings between \displaystyle+V_{\rm peak} and \displaystyle-V_{\rm peak}.^ Since the maximum value of sin( x ) is +1 and the minimum value is −1, an AC voltage swings between + V peak and − V peak .
  • PowerPedia:Alternating current - PESWiki 10 February 2010 11:011 UTC peswiki.com [Source type: Reference]

^ Maximum or peak value of the voltage, in volts (V) .
  • Principles of alternating current 10 February 2010 11:011 UTC www.tina.com [Source type: Academic]

^ Since the maximum value of is +1 and the minimum value is −1, an AC voltage swings between and .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

.The peak-to-peak voltage, usually written as \displaystyle V_{\rm pp} or \displaystyle V_{\rm P-P}, is therefore V_{\rm peak} - \left(-V_{\rm peak}\right) = 2 	imes V_{\rm peak}.^ The peak-to-peak voltage, usually written as or , is therefore .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ Therefore, AC voltage is often expressed as a root mean square (RMS) value, written as , because .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ For our 240 V AC, the peak voltage V peak is therefore , which is about 339 V. The peak-to-peak value of the 240 V AC is double that, at about 679 V. .
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

Power and root mean square

The relationship between voltage and power is:
\displaystyle P(t) = \frac{V^2(t)}{R} where \displaystyle R represents a load resistance
.Rather than using instanteneous power, \displaystyle P\left(t\right), it is more practical to use a time averaged power (where the averaging is performed over any integer number of cycles).^ Rather than using instanteneous power, , it is more practical to use a time averaged power (where the averaging is performed over any integer number of cycles).
  • Alternating current - Wikiversity 10 February 2010 11:011 UTC en.wikiversity.org [Source type: Reference]

^ AC electricity is more complicated than DC, so this unit will introduce some concepts and terms that we'll use for the rest of the course.
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

^ The ammeter will  register more than six times the normal operating current of the motor.
  • PAControl.com - Three-Phase Alternating Current Motors 10 February 2010 11:011 UTC www.pacontrol.com [Source type: FILTERED WITH BAYES]

Therefore, AC voltage is often expressed as a root mean square (RMS) value, written as \displaystyle V_{\rm rms}, because
\displaystyle P_{\rm time~averaged} = \frac{{V^2}_{\rm rms}}{R}
For a sinusoidal voltage:
V_\mathrm{rms}=\frac{V_\mathrm{peak}}{\sqrt{2}}
For non-sinusoidal waveforms, the relationship between \displaystyle V_\mathrm{rms} and \displaystyle V_\mathrm{peak} is different
  • For a triangle wave form: V_\mathrm{rms}=\frac{V_\mathrm{peak}}{\sqrt{3}}
  • For a square wave form: \displaystyle V_\mathrm{rms}=V_\mathrm{peak}

Example

.To illustrate these concepts, consider a 240 V AC mains supply.^ Consider AC motor suppliers with easy ordering options .
  • Alternating Current (AC) Motors Information | Business.com 10 February 2010 11:011 UTC www.business.com [Source type: General]

^ Diagram C is the waveform of the New Zealand mains supply: 230 volt AC 50 Hz, where the 230 is the rms value.
  • Alternating Current 10 February 2010 11:011 UTC www.nzart.org.nz [Source type: FILTERED WITH BAYES]

^ Incorporating numerous illustrations to reinforce key concepts, Essentials of Electric Motors and Controls reviews concepts such as, magnetism, AC current, frequency, and basic motor operation.
  • Electrical Theory | Alternating Current | Direct Current | Basic Electrical Theory Books, Videos and Libraries 10 February 2010 11:011 UTC www.licensedelectrician.com [Source type: Reference]

.It is so called because its RMS value is (at least nominally) 240 V. This means that the time-averaged power delivered is equivalent to the power delivered by a DC voltage of 240 Volts.^ Maximum or peak value of the voltage, in volts (V) .
  • Principles of alternating current 10 February 2010 11:011 UTC www.tina.com [Source type: Academic]

^ Don't confuse rms with mean or average value.
  • Alternating Current 10 February 2010 11:011 UTC www.nzart.org.nz [Source type: FILTERED WITH BAYES]

^ The average value of a waveform is also called its DC value .
  • EET 155 Unit 3: Introduction to Alternating Current and Voltage 10 February 2010 11:011 UTC people.sinclair.edu [Source type: Reference]

To determine the peak voltage (amplitude), we can modify the above equation to:
 V_\mathrm{peak}=\sqrt{2}\ V_\mathrm{rms}
For our 240 V AC, the peak voltage Vpeak is therefore \displaystyle 240 V 	imes\sqrt{2}, which is about 339 V. The peak-to-peak value \displaystyle V_{P-P} of the 240 V AC is double that, at about 679 V.

Further reading

  • Willam A. Meyers, History and Reflections on the Way Things Were: Mill Creek Power Plant - Making History with AC, IEEE Power Engineering Review, February 1997, Pages 22-24

See also

Template:Portalpar
  • Direct current
  • Line voltage
  • Mains power plug, AC power plug
  • Electricity
  • Electrical wiring
  • Heavy-duty power plugs
  • Utility frequency

External links

.

Simple English

File:City lights in
City lights viewed in a motion blurred exposure. The AC blinking causes the lines to be dotted rather than continuous.

An alternating current (AC) is an electric current of which magnitude and direction vary. That is the difference to direct current, whose direction remains constant.

The usual waveform of an AC power circuit is a sine wave, because this leads to the most efficient transmission of energy. But in certain applications there are used different waveforms, such as triangular or square waves.

When one speaks of alternating current one mostly refers to the form in which electricity is delivered to businesses and residences. But audio and radio signals carried on electrical wire are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.

Contents

History

William Stanley, Jr. designed one of the first practical devices to transfer AC power efficiently between isolated circuits. Using pairs of coils wound on a common iron core, his design, called an induction coil, was an early precursor of the modern transformer. The system used today was devised in the late nineteenth century, largely by Nikola Tesla. Contributions were also made by George Westinghouse, Lucien Gaulard, John Dixon Gibbs,Wilhelm Siemens and Oliver Shallenger. AC systems overcame the limitations of the direct current system used by Thomas Edison to distribute electricity efficiently over long distances.

The first modern commercial power plant that used three-phase alternating current was at the Mill Creek hydroelectric plant near Redlands, California in 1893. Its designer was Almirian Decker, a brilliant young engineer. Decker's innovative design incorporated 10,000 volt three phase transmission and established the standards for the complete system of generation, transmission and motors used today.

Further reading

  • Willam A. Meyers, History and Reflections on the Way Things Were: Mill Creek Power Plant - Making History with AC, IEEE Power Engineering Review, February 1997, Pages 22-24

Other pages

Other websites


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