JZS-71 AC commutator motor speed regulating circuit

The speed control circuit of JZS type AC commutator motor is shown in Figure 3-184. The power of the main motor M1 is 15/5kW
(meaning the maximum power is 15kW, the minimum power is 5kW, continuously adjustable), and the speed is 470-1400r/min; Mz is the blower on the
accessory motor for cooling the main motor; M3 It is the servo motor on the accessory motor (also called a remote control
motor); TG is an AC tachometer generator, used to measure the rotation speed, that is, the voltage emitted by it (which changes with the rotation speed of the motor
), which is full-wave rectified by the diode and resistor R The partial pressure causes the tachometer to display the corresponding speed. A low-speed limit switch sQ2 and a high-speed limit switch SQi are installed
    in the motor speed regulating mechanism. sQ2 ensures that the motor
can only start at the lowest speed; SQi ensures that the motor speed cannot exceed the highest speed to achieve safe operation.