The first type, due to this design, the starting button moment is not large, so it is not suitable for high-load equipment, especially those such as air compressors, which need a large starting button moment, which is not competent.

The second type, this is the main design of the previous, the starting performance is larger than the former, but it is only suitable for stable operation after starting, because its auxiliary winding is used as a starting, after starting it is completely dependent on the rotating magnetic field of the main winding, there is no so-called commutation, because the capacitor and the auxiliary winding after the motor speed reaches a speed, through the centrifugal switch and separation. They do not work, the fatal disadvantage of this motor is that once with some high-load equipment, such as air compressors, often turn around and slow down, and then start again through the auxiliary winding, so it is not suitable for many places, usually only used in fans and other places have some use, but has been replaced by the third type of motor.

The third type, its principle is that it has both the main winding, there are auxiliary winding, there are centrifugal switches, the auxiliary winding and the main winding work together, and the first type of said kind of similar, but so the starting performance is reduced how to do? They pass the centrifugal switch, this switch is a double-throw switch, so that when starting, a large-capacity capacitor [commonly known as the starting capacitor] (we also know that the larger the capacitance, the larger the phase shift current, the better the starting performance, but too large the winding will heat) So, this motor, that is, at low speed, the motor is incorporated into the use of large capacitors, The current provided by this large capacitor usually exceeds the rated current of the winding, and under such a high current drive, the rotating magnetic field is very strong, thus driving the high button moment output of the rotor to rotate.