Can anyone help me troubleshoot a motor on a treadmill? I don't know a lot about motors so please pardon my basic questions.
The motor has brushes and the label says 90VDC. It has 2 wires going into it, one comes from the control board and the other comes from a transformer like looking thing (field coil?) that in turn comes from the control board. When I try to make it run, it shows -70VDC at both terminals on the control board. When I remove the wire at the control board that goes to the coil, the wire reads -70VDC and the terminal reads 0VDC. When I remove the wire going to the motor, the terminal reads -55VDC and the wire reads 0VDC. I am reading the voltage with the black wire of the DVM on the chassis and the red wire on the terminal. Since I'm getting -70V, should I suspect the control board? But shouldn't the motor run even with negative voltage? Are there other tests I can perform that would rule out the motor?
Thanks for your help.