I checked out a sewage pump today with questions of why the breaker was tripping every once in while (actually only twice in about 4 to 5 days) I think I may have found the problem in a wire that had a "nick" in it that fed the timeclock that operates the pump that was laying up against the rough edge of the time clock. I'm thinking that the vibration of the motor was possibly causing the wire to short out, but don't know for sure since I didn't see any burn't marks on the timeclock, (that is until I started to get a amp reading and it blew up in my face:(
But laying this thought aside, I took amp readings on the motor phases. The voltage is around 213 volts on each leg.
The nameplate at 200 volts is showing 15.4 amps. The actual amperage is only around 7.7 amps. I don't understand why the amperage is so low. I disconnected the motor wires from the rest of the circuit and checked to see if one was shorted out to ground and they were not. I checked the motor numerous times and the breaker never did trip. Any ideas why I would get so low amperage when the nameplate is calling for twice what it was pulling??
When I left I had the pump coming on and off with the timeclock like it was suppose to. The customer is suppose to check it later and give me a call. I hope it is fixed but the amperage puzzles me. Thanks for the input.. Steve
