Wednesday, September 16, 2009

Electric motor



Generator

Main article: Electrical generator

Generator is the device that converts mechanical energy at its prime mover to produce constant electrical energy at its output.In more technical words it is a dynamic electrical energy machine. Generator is classified into two types: AC generator and DC generator.

The basic requirements for a dynamically induced emf to exist are the following: (1) A steady magnetic field (2) A conductor capable of carrying current (3) The conductor to move in the magnetic fiAC Generator

AC generator is the generator that converts mechanical energy at its prime mover into AC electricity.

AC generator is classified into several types:
Asynchronous AC generator or induction 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, either external DC source or mounted DC source.


DC Generator

DC generator is the generator that produces DC current. Example of a DC generator is dynamo.


Motor
Main article: Electric motor


Motor is the device that converts electrical energy at its input to produce mechanical energy. Motor is classified into two types: AC motor and DC motor.


AC Motor
Main article: AC motor

AC motor is the motor that converts AC electrical energy at its input into mechanical energy.

AC motor is classified into several types:
Asynchronous AC motor or induction AC motor
Synchronous AC motor


DC Motor
Main article: DC motor


DC motor is the motor that converts DC electricity into mechanical energy. Its main components are stator, rotor, windings (field windings and armature windings) and commutator.

DC motor is classified into five types:
Compounded DC motor
Permanent magnet DC motor
Separately excited DC motor, a DC motor whose field circuit receives power from a separate constant voltage supply.
Series DC motor, a DC motor whose field windings consist of relatively few turns and connected in series with the armature circuit.
Shunt DC motor, a DC motor whose field circuit receives power directly across the armature terminals.

Losses in DC motor are brush drop losses, core losses, mechanical losses and stray losses.


Transformer
Main article: Transformer
Transformer is the device that converts AC voltage from one level to another level higher or lower, or even to the same level without changing the voltage. It works based on the principle of mutual induction, so its power remains approximately constant, where as frequency also remains the same.