AC motor

Alternating current periodically changes direction, usually 50-60 times per second. Some AC motors have a rotor to which power is supplied through a manifold, as in DC motors. But many engines of this type there are no connections to the rotor. Their action is based on the principle of induction. Alternating current passing through the stator that generates a rotating magnetic field, as would be the case of rotation of the permanent magnet. This is a sliding field directs a current in the direction of the windings of the rotor, magnetizing it. As a result, the rotor rotates because it makes the pole move in a circle magnetic field rotates around the rotor.
Often the rotor consists of copper or aluminum rods, the ends of which connect the two metal rings. The assembled rotor is like a cage, and such machines are called motors with "squirrel cage", or squirrel-cage motors.