voltage moniter and phase imbalance
voltage moniter and phase imbalance
(OP)
I just installed a Wagner 3-phase voltage moniter on a 3-phase 480VAC fan motor and here's the rundown:
-This motor has been replaced twice due to a phase loss burning it up. So I suspected power problems.
-now it shuts off, and stays off, until the main circuit is reset.
-went to check on the voltage moniter, and it is set to a 15% voltage imbalance as its maximum tolerance, and a 10% phase imbalance as its maximum tolerance.
My question is what are the proper acceptable ranges for 480V 3 phase, at what point should I call the power company if I read 25 or so imbalance warnings on the moniter's trend log?
-This motor has been replaced twice due to a phase loss burning it up. So I suspected power problems.
-now it shuts off, and stays off, until the main circuit is reset.
-went to check on the voltage moniter, and it is set to a 15% voltage imbalance as its maximum tolerance, and a 10% phase imbalance as its maximum tolerance.
My question is what are the proper acceptable ranges for 480V 3 phase, at what point should I call the power company if I read 25 or so imbalance warnings on the moniter's trend log?





RE: voltage moniter and phase imbalance
I would then do the same at the main panel. This will identify the location of the problem. If the voltages at the main panel are uinbalanced call the utility. They will probablly appreciate that you have first checked out your own wiring before calling them.
They may be quite helpful. I have had the utility adjust transformer taps to compensate for chronically low voltage on one phase.
respectfully
RE: voltage moniter and phase imbalance
BK
RE: voltage moniter and phase imbalance
The main problem is overheating due to negative sequence currents in the rotor winding.
RE: voltage moniter and phase imbalance
You appear to have a serious problem with your line voltage balance. It may not necessarily be the fault of the utility, your own facility loading may be the culprit. Rather that continuing to throw money at it to buy hardware, a prudent investment at this time may be to bring in a professional who can analyse your power quality.
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