Single-phase asynchronous motors refer to asynchronous motors powered by single-phase power sources. They are widely used in places where only single-phase AC power is available, such as household appliances, office Spaces, and power tools. Structurally speaking, the stator of a single-phase asynchronous motor is similar to that of a common three-phase squirrel-cage asynchronous motor, except that the shaded-pole stator has protruding magnetic poles. There are generally two sets of windings on the stator, namely the working winding and the starting winding. By connecting capacitors in series, the axes of the two windings are spatially offset by a certain electrical Angle to assist in the start-up of single-phase motors. The phase-shifting function of capacitors is used to improve the power factor and efficiency of single-phase motors and reduce electromagnetic noise.

If a single-phase asynchronous motor is used improperly or for too long, it is bound to malfunction. In severe cases, electric shock may occur to people. Here, taking the motors of commonly used household appliances such as electric fans, washing machines, and air conditioner compressors as examples, we introduce the causes of common faults and their troubleshooting methods.

Single-phase asynchronous motors of household electric fans, washing machines and air conditioner compressors have many faults in daily use. The main faults include: motor overheating, excessive noise or vibration when the motor rotates, motor speed lower than normal speed, inability to start when powered on, small or slow starting torque and uncertain direction, electrified motor casing, short circuit or open circuit of motor windings, grounding and other faults or types.

Common maintenance methods for single-phase asynchronous motors of electric fans: Use a voltmeter to check if the motor is leaking electricity. Observe the rotational speed of the electric fan to see if the motor can start running. If not, the starting torque of the motor is small. Check the temperature rise of the electric fan. If the motor windings and bearings malfunction, after being powered on for about one hour, the temperature will rise to be extremely hot to the touch. If you place your hand on the motor housing after running for one hour, the motor is normal. Check the noise of the motor. If the electric fan operates at various speeds, a normal “rustling” sound can be heard, but there is no mechanical or electromagnetic noise.