Micro DC motor thyristor speed regulating circuit 2

The circuit consists of speed given, phase-shifting pulse, thyristor rectification and feedback links. Figure 16-82 shows the speed regulation circuit of
the DC motor of the RDJ-77 multifunctional processing machine . It is suitable for constant torque speed regulation. It is used for 220V series-wound DC motors (for electric tools), with a rated power of 120W, a maximum power of up to 250V, a speed adjustment range of 0-14000r/min, and a mechanical property hardness ≥90%.     Adjust the potentiometer RPa to change the speed of the motor. Through switch SA, two different DC voltages of the excitation power supply can be provided to adapt to the torque requirements of different loads.