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Variable speed DC motor circuit

Published on Apr 11 2011 // Motor Control circuits

Variable speed DC motor circuit board product is very expensive, and I in the maintenance of a packaging machine by a DC motor speed control board, the mapping and create success, is dedicated to everyone.
         This simple circuit board, the cost is not high, making easy to make a simple analysis of the circuit: 220V AC by the step-down transformer T, P2 rectifier, V5 by 9V DC voltage regulator, the LM324 quad op amp integrated chips provide work power. P1 rectifier output to provide DC excitation power. Thyristor rectifier controlled by the P4 are 0-200V DC, then the motor armature, the motor stepless speed regulation. R1, C2 is the RC element, protection thyristor V1. R3 is a string in the armature circuit for current sampling, when the motor is overloaded, R3 increases the voltage, the rectifier D1, C3 regulator, W1 adjusted to 12 feet into the LM324, compared with 13 feet out from 14 feet to 1 feet, triggering V7 SCR, D4 LED red LED light, pulled the pin 6 voltage V1 can not trigger the SCR, to protect the motor. The size of the motor overload current regulation by the W1. Mains zero crossing, phase control is by the R5, R6 blood pressure, P3 rectification, isolated by the 4N35 get a pulsating DC into 14 feet, 8 feet to 5 feet from the output is a pulse wave, adjust potentiometer is adjusted W2 6 feet the voltage magnitude, can change the pulse width, pulse center coincides with the alternating current zero-crossing point, making the zero-crossing triac conduction well, D4 is the overload indication, D3 is the work instructions, W2 is the motor speed stepless potentiometer. After making the circuit as long as the components pass can be used without adjustment. I have tried 100W-1000W motor, reliable, convenient adjustment and excellent performance.

 Variable speed DC motor circuit 1

Variable speed DC motor circuit 2