Electrical machines are categorized into two..

Motor.
Generator.
There are two kinds of motor.

AC motor.
DC motor.
There are two kinds of three phase motor.

Synchronous motor.
Asynchronous motor.
The essential difference between asynchronous and synchronous motor , slip presents in asynchronous engine .At running condition slip of an asynchronous motor lies from 0 to at least one 1. . In asynchronous electric motor both starting and working torque is necessary. Asynchronous motor has moderate beginning torque . Asynchronous motor can be a single fed electric motor.In asynchronous engine 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: Primary workhorse of the energy generation industry; they are rotated mechanically by a primary mover at synchronous speed and it 12v Motor creates three phase electricity. Image of PMA found in cars:
2. Synchronous motor: These are constant speed three phase devices capable of working at synchronous velocity. They are mostly found in constant quickness mechanical drives. They are more efficient compared to induction motors.
A synchronous machine has derived its name from the idea 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 swiftness i.electronic. 3000 rpm. This is achieved through unique constructional features in manufacturing this types of machines. There is 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. This is why ‘three phase’ is added with synchronous machine name.