Split-Phase Motor Working Principle

This motor used in major motor­ized appliances and it is primarily employed in large units, such as washing machines. However, you might encounter one in a large electric fan.

A split-phase motor consists of two windings (coils). One is used to start the armature turning, and the other is used to keep the armature turning at a constant speed. Once the motor starts and attains running speed, the starting coil is cut from the circuit and the running coil assumes the task of keeping the motor running.

This is done by means, usually, of a centrifugal switch (or governor), that has a spring-controlled arm.On the end of this arm is a contact point. When this contact point “breaks” away from a mating contact point, the circuit is broker. and the starting coil shuts off.