Electrical machine

An Electrical machine is a device that converts mechanical energy to electrical energy or vice versa, and changes AC voltage from one level to another level.

Generator

A 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 field

AC 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 power i.e.,constant power P=V*Iby taking mechanicalenergy as input. Example of a DC generator is dynamo.

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

AC motor is the motor that converts AC electrical energy at its input into mechanical energy.
AC motor is classified into several types:
* Asynchronous motor or induction AC motor

* Synchronous motor

DC Motor

DC motor is the motor that converts DC electricity into mechanical energy. Its main components are stator, rotor, 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

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 frequency. It works based on the principle of mutual induction, so its power remains approximately constant, where as frequency also remains the same.