GFCI Supplied to a Motor

Status
Not open for further replies.
R

rmonroe

Member
Today at work we hook-up some modular GFCI?s. I forgot to bring home the data sheet so I will try to explain them to this forum. They are rated at 120 VAC, 20 amp and single phase. They are rectangular in shape, black in color and they are panel mount type. They have two wires on the top (Black and White) which is label the Line Side. On the bottom, which is label Load Side, the color of the wire is also Black and White. On the front of these GFCI?s there is a Test bottom and a Reset button. Also there is a green LED to indicate the system is not in ground fault.

We tied in a NEW small 120 VAC induction motor which drives a pump to the Load Side. This is a standard motor with a centrifugal switch for the start winding. As soon as we try to start to motor we get a ground fault (the green LED is no longer lit). We have triple checked all the wiring and switched to deferent supply circuits, but no luck. I did have the technician remove the GFCI from the circuit and run the motor without the GFCI. It runs with no problems. I also removed the ground of the motor and checked for any leakage from motor frame to building ground. I do get a reading of about 6 to 7 volts on my meter.

This is my problem?


Thank you

rmonroe
 
Cheap motor.

I believe the most common cause of so called nuisance tripping of motors is their start and/or run capacitors leaking to their case and then to ground.
 
Re: GFCI Supplied to a Motor

rmonroe said:
I also removed the ground of the motor and checked for any leakage from motor frame to building ground. I do get a reading of about 6 to 7 volts on my meter.

This is my problem?
Click to expand...
Yes, this is the problem. If the motor runs with the grounding wire disconnected, and also insulated from any other grounded surface, then the problem is definitely within the motor. Is it new enough for warranty coverage?

Try disconnecting the motor completely from the wiring, and use an ohmmeter between each power lead and the motor frame. There should be infinite resistance. If not, the motor should be rewound or replaced. This is a safety issue.
 
Status
Not open for further replies.
Top