Simple control circuit of single-phase capacitor motor

Single-phase capacitor motors have large starting torque, small starting current, and high power factor. They are mainly used in household appliances, such as electric fans, washing machines, etc. In order to facilitate maintenance and installation, the following introduces the common wiring methods of this type of motor.

Figure 1 (a) is a reversible control circuit. By operating the switch S2, the direction of the motor can be changed. This circuit is generally used in household washing machines.

Figure 1 (b) shows a wiring circuit with an auxiliary winding. By turning the switch S, the tap of the auxiliary winding can be changed, that is, the actual withstand voltage of the main winding can be changed, thereby changing the speed of the motor. This wiring method is often used in electric fans.

Figure 1 (c) shows the wiring circuit of a capacitor motor with reactor speed regulation. Due to the series connection of the reactor winding (which plays a role of reducing voltage in the circuit), the speed can be changed by adjusting the series connection amount of the reactor winding. This method is widely used in household electric fan circuits. When starting the motor, first turn to "1", which is the high gear. At this time, the reactor is not connected to the circuit, so that the motor starts at full voltage, and then turn to "2" or any gear to adjust the motor speed.

Figure 1: Single-phase capacitor motor circuit