Single phase asynchronous motor is powered by single-phase AC power supply. There is a set of single-phase working winding on the motor stator. The magnetic potential generated by single-phase winding is positive and negative alternating pulse magnetic potential, which can not generate starting torque; A set of auxiliary windings shall also be provided on the motor stator, or corresponding measures shall be taken on the magnetic circuit structure to make the motor have self starting ability.

Single phase resistance starting asynchronous motor

The stator of the motor has main winding and auxiliary winding. Their axes differ by 90 ° in space. The auxiliary winding with generally large resistance value is connected to the power supply together after being connected in parallel with the main winding through the starting switch. After the motor is started, when the speed is close to the synchronous speed, the start switch is opened, the auxiliary winding is disconnected from the power supply, and the main winding works alone. This kind of motor is characterized by simple structure, low cost and stable operation, but the starting current is large, up to more than 5 times of the rated current, and the maximum will be 9-10 times; The starting torque, overload capacity and rated force and energy index of the motor are general. Therefore, the power range of this kind of motor is generally tens to hundreds of watts, which is suitable for small machine tools, fan and massager with no special requirements for starting torque.

Single phase capacitor starting asynchronous motor

The structure of the motor is the same as that of the resistance starting type, but a starting capacitor with large capacity is connected in series in the secondary winding circuit. In addition to the advantages of resistance starting motor, the motor has the characteristics of significantly increasing starting torque and small starting current. However, due to the high price of high-capacity capacitor, the power range of capacitor starting motor is generally hundreds of watts, which is suitable for high starting torque or full load starting occasions, such as small air compressor, refrigerator and pulverizer.

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