Electrical machines are classified into two..
Motor.
Generator.
There are two types of motor.
AC motor.
DC motor.
There are two types of three phase motor.
Synchronous motor.
Asynchronous motor.
The essential difference between asynchronous and synchronous engine , slip presents in asynchronous electric motor .At running condition slide of an asynchronous motor lies from 0 to 1 1. . In asynchronous motor both starting and running torque is necessary. Asynchronous electric motor has moderate beginning torque . Asynchronous motor is usually a single fed motor.In asynchronous motor field is stationary armature rotates .
Three phase synchronous machines possess a stationary three phase armature and a wound rotor. They are of two types:
synchronous generator or Alternator: Main workhorse of the power generation industry; they are rotated mechanically by a prime mover at synchronous acceleration and it creates three phase electricity. Image of PMA used in cars:
2. Synchronous motor: They are constant speed three phase devices capable of working at synchronous velocity. They are mostly found in constant velocity mechanical drives. They are better in comparison to induction motors.
A synchronous machine has derived its name from the concept that the rotor will rotate in synchronicity with the rotating magnetic field.
Simply speaking, for a 2 Pole machine (electric motor) the rotating magnetic field rotates at 3000 rpm; the rotor of synchronous machine also rotates at the same velocity i.e. 3000 rpm. This is achieved through unique constructional features in production this types of machines. There is 12v Motor absolutely no slip in synchronous devices like regular induction motors.
Normally three phase supply is available commercially and the look is also meant for the same. That is why ‘three phase’ can be added with synchronous machine name.