Washdown transfer pump, PowerFlex 525, 3hp, 480VAC. Motor sits outside on a pad with its own junction box. For three weeks now the first start of the morning trips F013 Ground Fault. Reset it, start again, runs clean all day. Next morning, same again.
We swapped the drive for the spare. Next morning the spare did it too. I pulled the motor lead lugs at the drive and went over them, tight, no green, nothing burnt.
Two drives, same fault, same time of day. A lad at our sister plant said these are known for being touchy on ground fault, so is there a way to back the detection off a bit? Feels oversensitive first thing and nothing else on that pad complains. Or is the first start of the morning telling me something about a motor that sits outside all night, because I'm out of ideas after two drives?
Don't make it less touchy, the drive's protecting itself and the motor. Why the morning is the question. Damp, I reckon. Damp nights, cold? Megger the motor and cable before the first start, then again after it's run an hour. Two readings, not one.