Frequency-sensitive resistor started wound rotor asynchronous motor manual commutation circuit

The picture shows a manual reversible starting circuit. Press the forward start button STF, and the other pair of normally closed contacts of STF are disconnected, cutting off the circuit of the reverse coil KMR. At this time, the forward coil KMF is attracted, and the wound rotor motor is connected in series with the frequency-sensitive resistor L, entering In the starting state, its speed gradually increases. When the speed rises to about 70% of the rated speed, when the run button SN is pressed, KM3 absorbs and protects itself, the frequency-sensitive resistor is short-circuited, and the motor enters full voltage operation. When the work is completed, press STP and stop the vehicle. In the same way, when the STR button is pressed, the motor enters reverse start, and when SN is pressed, the motor enters full voltage operation.