En route to getting the off-the-peg DC-51 motor speed controller to better suit my small milling machine, I had a go at working out what the circuit is. Approx circuit of DC-51 motor speed controller ...

I was planning to use the opto-coupler speed sensor as part of a motor speed control – making the motor into the VCO block in a phase-locked loop. When this technique works, using it is simple: put ...

All three signals are sent to theinput-capture and timer/counter peripheral for speed measurement. Figure48. Vector control flow diagram. At every carrier-frequency interrupt, three PWM signals ...