A typical AC motor consists of two part: an outside stationary stator having coils supplied with AC current to produce a rotating magnetic field, an inside rotor attached to the output shaft that is given a torque by the rotating field. There are two fundamental types of AC motor depending on the type of rotor used:

The synchronous motor, which rotates exactly at the supply frequency or a sub-multiple of the supply frequency.

The induction motor, which turns slightly slower, and typically(though not necessarily always) takes the form of the sqirrel cage motor.

For higher-power applications where a poly-phase  electrical supply is available, the tree-phase AC induction motor is used. The phase differences between the three-phases of the poly-phase electrical supply create a rotating electromagnetic field in the motor