Two types of AC Induction motors:
• Squirrel-Cage. In squirrel-cage motors, the rotor consists of permeable metal containing embedded strips of magnetic material. As the stator magnetic field rotates, the field interacts with the magnetic field established by the magnetic poles of the rotor, causing the rotor to turn at nearly the speed of the rotating stator magnetic field.
• Wound-Rotor. In wound-rotor designs, the permanent magnets used in the squirrel-cage motor are replaced by a rotor having windings. In this motor, when the stator magnetic field rotates and the rotor windings are shorted, the stator magnetic field motion induces a field into the wound-rotor, once again causing the rotor to turn at nearly the speed of the rotating stator magnetic field.