Single phase induction motor is a device which can transform electrical energy into mechanical energy. Though it is in a small size, but it is convenient as it solely needs single phase power source to supply and is applied to the fields of industry , agriculture, as well as life electric appliance. Typical applications are: washing machine, electric fan, refrigerator, air conditioning, water pump, blower, juice machine, soya bean milk machine, etc.
In structure, the ordinary single phase induction motor is similar to the multi-phase squirrel cage motor, except for the stator winding arrangement. The single phase winding generates two equal positive and counter rotating magnetic potential waves, and when the motor is stationary, it would generate two torques, with same size and opposite directions, which offset each other to result in the motor without a starting torque. If the motor is started with auxiliary means, the motor will produce a synthetic torque starting at the starting direction.
* Starting single-phase asynchronous motor
* Capacitor start single-phase induction motor
* Capacitor run single-phase induction motor
* Double valued capacitor single-phase asynchronous motor
* Shaded pole single-phase asynchronous motor
The rotor and the stator wingding are the basic parts of a single-phase induction motor. The stator winding helps the rotor to rotate. In the following figure doesn’t show the iron layer lamina installed inside rotor for clear viewing on the rotor bars.
The winding has got 2 components: One main winding and an auxiliary winding. A capacitor is connected to the auxiliary winding which is placed perpendicular to the main winding.
The capacitance of the capacitor is the key determinant of the time from motor startup to the synchronous speed. When the motor at synchronous speed, the slip is very small and the average torque becomes zero.