- Electrical machine
Electrical machine is a device that convert either
mechanical energy toelectrical energy or vice versa, and changeAC voltage from one level to another level.Electrical machines are divided into three parts:
Generator
Generator is the device that convertsmechanical energy at its to produce constantelectrical energy at its output.Generator is classified into two types:AC generator andDC generator .AC Generator
AC generator is the generator that convertsmechanical energy at its intoAC electricity .AC generator is classified into several types:
*Asynchronous AC generator orinduction AC generator , an AC generator whose field current is supplied by magnetic induction into the field windings.
*Synchronous AC generator , an AC generator whose magnetic field current is provided by a separate DC current source, eitherexternal DC source ormounted DC source .DC Generator
DC generator is the generator that convertsmechanical energy at its intoDC electricity .DC generator is classified into several types:
*Cumulatively compounded DC generator , a DC generator whose bothshunt field andseries field are present and their effects are additive.
*Differentially compounded DC generator , a DC generator whose effects ofshunt field andseries field are subtractive.
*Separately excited DC generator , a DC generator whosefield flux is produced by a separate power source independent of the generator.
*Series DC generator , a DC generator whosefield circuit is in series with thearmature .
*Shunt DC generator , a DC generator whosefield circuit is connected directly across the terminals of the generator.Motor
Motor is the device that convertselectrical energy at its input to producemechanical energy .Motor is classified into two types:AC motor andDC motor .AC Motor
AC motor is the motor that convertsAC electrical energy at its input intomechanical energy .AC motor is classified into several types:
*Asynchronous AC motor orinduction AC motor
*Synchronous AC motor DC Motor
DC motor is the motor that convertsDC electricity intomechanical energy . Its main components arestator ,rotor ,windings (field windings andarmature windings ) andcommutator .DC motor is classified into five types:
*Compounded DC motor
*Permanent magnet DC motor
*Separately excited DC motor , a DC motor whosefield circuit receives power from a separate constant voltage supply.
*Series DC motor , a DC motor whosefield windings consist of relatively few turns and connected in series with thearmature circuit.
*Shunt DC motor , a DC motor whosefield circuit receives power directly across thearmature terminals.Losses in DC motor are
brush drop losses ,core losses ,mechanical losses andstray losses .Transformer
Transformer is the device that convertsAC voltage from one level to another level higher or lower, or even to the same level with out changing the voltage.References
Chapman, Stephen J. 2005. Electrical Machinery Fundamentals. 4th Ed. New York: McGraw Hill.
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