Electrical machine

Electrical machine is a device that convert either mechanical energy to electrical energy or vice versa, and change AC voltage from one level to another level.

Electrical machines are divided into three parts:

Generator
Generator is the device that converts mechanical energy at its prime mover to produce constant electrical energy at its output. Generator is classified into two types: AC generator and DC generator.

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 converts mechanical energy at its prime mover into DC electricity.

DC generator is classified into several types:
 * Cumulatively compounded DC generator, a DC generator whose both shunt field and series field are present and their effects are additive.
 * Differentially compounded DC generator, a DC generator whose effects of shunt field and series field are subtractive.
 * Separately excited DC generator, a DC generator whose field flux is produced by a separate power source independent of the generator.
 * Series DC generator, a DC generator whose field circuit is in series with the armature.
 * Shunt DC generator, a DC generator whose field circuit is connected directly across the terminals of the generator.

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 AC motor or induction AC motor
 * Synchronous AC motor

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
Transformer is the device that converts AC voltage from one level to another level higher or lower, or even to the same level.