DC field slowly shorting?
DC field slowly shorting?
(OP)
I have a 250 HP dc motor that seems to slowly short the shunt field. The motor is a shunt, series motor. The shunt field had similar problem two years ago. I am looking at application speed. I was also considering if there is something in the Drive that could be out of adjustment and slowly cooking the field. I am considering having a tech. in to check out the drive. I was looking for feedback as to what is most common problem that might cause my situation?





RE: DC field slowly shorting?
Does the motor get hot at standstill? Does it smell burnt or hot? Turn-to-turn shorts can develop over time if the field winding gets hotter than normal. You need a "drive doctor". Soon!
RE: DC field slowly shorting?
RE: DC field slowly shorting?
I reinstalled the fuses and now the field current was 125% or 130% of nameplate. Had to readjust the field resistor. It was really amzing what a little bit of copper oxide was doing to the circuit! Somebody else just kept adjusting the field resistor to compensate for the copper oxide instead of cleaning it out. A bit like running with a pebble in your shoe!
Mike Cole, mc5w@earthlink.net