Ac Shaded Pole Motor

The Shaded Pole motor is one type of induction motor with very low noise about 30-60dB(A), low vibration, very long lifetime, low speed, low power (about 6 - 100W), and stable running. It can be widely used for office or home appliances that need very low noise environment.
It is a single-phase induction motor that uses its own method to produce starting torque. Instead of a separate winding like the split-phase and capacitor motors, the shaded-pole motor's start winding consists of a copper band across one tip of each stator pole. This copper band delays the magnetic field through that portion of the pole. When AC power is applied, the main pole reaches its polarity before the shaded portion of the pole. This action causes the shaded poles to be out of phase with the main poles and a weak rotating magnetic field is produced. Because of the low-starting torque, it isn't feasible to build motors of this type larger than 1/ 20 horsepower.
Because of its simple construction, it is usually the lowest priced motor available. However its low starting torque, except when used in conjunction with speed reduction drives makes it suitable in most cases only for direct fan and blower applications. Power loss is nearly constant between no load and load. Therefore light loading does not reduce motor losses significantly.