I am having a problem with a DC motor controller I have. There is no schematic available that I can see.
It requires a 5k potentiometer (which I bought from Radioshack). 120VAC input, and 110vDC output. There are 4 LED's on the circuit board:
AC voltage LED is always on, so I assume this means the presence of AC voltage. SCR trig is on as long as the motor is. Sped Cntrl lit up when the Pot was wired up properly, so I know that is good. Cur Lim is current limiting, only activated when the motor is trying to draw over the rated 11amps of the controller.
Now here is the thing, I turn the shaft of the potentiometer and the motor variates its speed fine. But then about half way through the rotational travel of the shaft, the motor comes to a fairly sudden halt. Also, the SCR trig LED is no longer active. I thought maybe it was something to do with the 2HP motor I am driving, so I tried it with another 4/5HP DCmotor I have sitting around. Same thing! My thought was that maybe the motor has reached its max RPM, but that does not make sense. The max for the 4/5HP motor is 5000RPM, and max for the 2HP motor is 6750RPM.
Not quite sure what to do here, any ideas?