Working principle of covered pole motor

Covered pole motor is a simple self-starting AC single-phase induction motor, which is a small squirrel cage motor. One of the auxiliary windings is surrounded by a copper ring, also known as a cover ring or drain ring. This copper ring is used as the secondary winding of the motor. The salient features of the covered pole motor are simple structure, no centrifugal switch, large power loss, low motor power factor and low starting torque. They are designed to be small and have a very low power rating. The speed of the motor is as precise as the frequency of the power supply applied to the motor, which is commonly used to drive clocks. The covered pole motor only rotates in a specific direction, so the motor cannot rotate in the opposite direction, the blocked pole coil causes loss, the motor efficiency is low, and its structure is simple. These motors are widely used in household fans and other small capacity appliances.