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What are the main components in the control circuit of an electronically speed-controlled motor? The control circuit for such motors typically uses a half-wave thyristor rectifier circuit with freewheel diodes. It includes the following steps. 1. Phase-shifting and triggering section: A triggering circuit using a single transistor with a sawtooth wave as the synchronous voltage, or a thyrister with a trapezoidal wave as the synchronous voltage. By adjusting the main potentiometer, if the set voltage is increased, the control voltage that triggers the circuit rises as well, which causes the output pulse of the trigger to shift forward. The phase shift angle α of the thyristor decreases, and the excitation voltage of the clutch increases, resulting in an increase in speed. Conversely, if the set voltage is decreased, the speed drops. https://www.zuolidianji.com/uploads/ueditor/20200717/1-200GG04I5E9.jpg 2. Given voltage source A stable direct current voltage is generated by a bridge rectifier with RC π-filter circuit and a Zener diode, which serves as the given voltage. By adjusting the main potentiometer, the magnitude of the applied voltage can be changed, thereby enabling speed control of the motor. 3. Comparison and amplification stage: The given voltage is compared (subtracted from) the feedback signal, and the resulting signal is amplified by a transistor. The amplified control signal is then fed into the flip-flop (after being limited in both positive and negative directions before input). 4. Speed measurement negative feedback circuit: The tachogenerator is connected coaxially with the load; it converts the rotational speed into a three-phase AC voltage, which is then rectified using a three-phase bridge circuit and filtered by capacitors to produce a negative feedback DC signal. The amount of feedback can be adjusted by tuning the speed negative feedback potentiometer. The purpose of using negative speed feedback is to increase the stiffness of the mechanical characteristics of the electronically controlled motor, so that its speed does not change due to variations in the load. https://www.zuolidianji.com/