Electrical machines are 12v Motor classified into two..
Motor.
Generator.
There are two types of motor.
AC motor.
DC motor.
There are two kinds of three phase motor.
Synchronous motor.
Asynchronous motor.
The basic difference between asynchronous and synchronous engine , slip presents in asynchronous electric motor .At running condition slip of an asynchronous engine lies from 0 to 1 1. . In asynchronous motor both starting and operating torque is necessary. Asynchronous motor has moderate beginning torque . Asynchronous motor is certainly a single fed engine.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 power generation industry; they are rotated mechanically by a prime mover at synchronous velocity and it creates three phase electricity. Picture of PMA found in cars:
2. Synchronous motor: They are continuous speed three phase devices capable of working at synchronous speed. They are mostly used in constant rate 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.
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 speed i.electronic. 3000 rpm. This is achieved through unique 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’ can be added with synchronous machine name.