An electric motor driven by an alternating current consists of two basic parts:

~an outside stationary stator having coils supplied with alternating current to produce a rotating magnetic field, and
~an inside rotor attached to the output shaft that is given a torque by the rotating field

The AC motor has two types which depend on the type of rotor used. The first is the synchronous motor, which rotates exactly at the supply frequency of a sub-multiple of the supply frequency. The rotor’s magnetic field is either generated by current delivered by a permanent magnet or through slip rings. The second type is the induction motor that turns slightly slower than the supply frequency. The rotor’s magnetic field is created by an induced current.