Shaded pole AC motor with simple, low cost and low running noise or other reasons is widely used in electric fans, hair dryer, vacuum cleaner small household appliances. Shaded pole motors only the main winding and no start winding.

However, the stator poles Department and has a short-circuit ring, also known as "shaded pole ring electrode", when the motor is powered, the main part of the generated magnetic field, this magnetic field is fluctuating, the motor will not rotate. But in the short circuit current generated ring, so that magnetic pole on the quilt part of the magnetic field generated, not covering the part of the magnetic field than some lag, which constitutes a rotating magnetic field, the motor will rotate the rotor start to work. In fact, this short loop is equivalent to the motor start winding up.

 This is the origin of shaded pole motor.