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.

12v Motor synchronous motor.
Asynchronous motor.
The basic difference between asynchronous and synchronous engine , slip presents in asynchronous electric motor .At running condition slide of an asynchronous engine lies from 0 to 1 1. . In asynchronous motor both starting and working torque is necessary. Asynchronous motor has moderate beginning torque . Asynchronous motor is a single fed electric 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: Primary workhorse of the energy generation industry; they are rotated mechanically by a prime mover at synchronous rate and it creates three phase electricity. Picture of PMA used in cars:
2. Synchronous motor: They are continuous speed three phase machines capable of running at synchronous velocity. They are mostly found in constant acceleration mechanical drives. They are better compared 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.

In other words, 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.electronic. 3000 rpm. This is achieved through particular constructional features in production this types of machines. There is no slip in synchronous machines like regular induction motors.

Normally three phase supply is available commercially and the look is also designed for the same. This is why ‘three phase’ is certainly added with synchronous machine name.