A: there are many kinds of AC asynchronous motors (single-phase motors), but most of the differences in series mainly lie in their starting mode. There are two main types: phase separation starting and cover starting (also known as mask starting), in which phase separation starting is also called split phase starting, and it can be divided into resistance phase separation and capacitance phase separation. The latter is widely used and has many varieties. There are three forms: single-valued capacitance starting, single-valued capacitance starting and running and double-valued capacitance. In addition to the above two types, there is a single-phase AC motor called series excitation motor, which should be strictly called AC and DC dual-purpose motor.


(1) Phase - starting single - phase AC asynchronous motor.


This kind of motor has two sets of windings, one of which is called starting winding, also known as secondary winding or auxiliary winding, and the other is called main winding, also known as working winding. In general, the two sets of windings are different in turn number, wire diameter and so on, but for special purpose motors, if both positive and negative steering motors are needed, such as washing machine motors, the two sets of windings will be exactly the same. The position of the main and auxiliary windings on the circumference of the stator core is 90 °difference (90 °for the 2-pole motor and 45 °for the 4-pole motor).


1.Resistance phase separation type. In the auxiliary winding circuit of the motor, a resistance is connected or the DC resistance of the auxiliary winding is greater than that of the main winding. Because the position of the two windings on the stator core circle is different by 90 °electric angle and impedance, the current in the two windings produces phase difference, thus producing starting torque and starting the rotor of the motor. when the rotating speed reaches about 80% of the synchronous speed, the power supply of the auxiliary winding is automatically disconnected by centrifugal switch, and the rotating magnetic field generated by the main winding makes the motor run. The circuit schematic diagram is shown in Fig. 18 / 1 (a).


2.single value capacitance starting type. The resistance in the resistance phase separation type is replaced by the capacitance (of course, the winding parameters will also change), that is to say, it becomes a single value capacitor starting single phase motor. The circuit principle is shown in Fig. 18 / 1 (b). 


3. single value capacitance starts and transports. Compared with the single-valued capacitor starting type, it can be seen from figure 18 ≤ 1 (c) that removing the centrifugal switch becomes this type of single-phase motor. The capacitor will be connected to the auxiliary winding circuit for a long time, so that the auxiliary winding will be electrified in both starting and operation. The structure of this type of motor is simple and widely used. 


4. Double capacitance type. The double capacitance type is the combination of the first two capacitor phase separation motor circuits. The circuit principle is shown in Fig. 18 / 1 (d). In general, the capacitance of the two capacitors is different. This type of motor has complex structure, but high efficiency and power factor, and is often used in equipment with large capacity.


What are the types of single-phase asynchronous motors? What are the structural characteristics of each other?