An electric conundrum

[Wade Lippman]

Solved, apparently 4 hours of sleep causes electrical problems.

I plugged my little Senco compressor into a GFCI outlet and it didn't work. I tried the vacuum also plugged in and it worked fine. I switched the plugs and the results were the same.

I then tried both at the same time and the compressor worked. Tried everything repeatedly to make sure, and the results were consistent.

I then plugged the compressor into a non-GFCI outlet and it worked fine. Though the GFCI outlet had nothing else on it, while the non-GFCI outlet was on the same circuit as a number of turned on lights.

If you can figure this one out you must be brighter than me; it seems impossible to me.

[Mike Vermeil]

My guess is something is wrong with the GFCI outlet. If you try the compressor in another GFCI outlet, I'll be it works.

[Byron Trantham]

Yep, I'd be looking at the GFCI outlet.

[Eric Haycraft]

My guess is that the polarity is backwords on it or something similar. Buy a 5 dollar outlet tester and check it.

Eric

[Rod Sheridan]

I've had the same problem occasionaly with induction motors on GFCI receptcles.

In each instance the GFCI has tripped when the centrifugal switch in the starting winding opened.

I don't have any measurements to back this up, however I would expect that the counter EMF produced in the starting winding when the switch opens, is causing a current that the GFCI thinks is an unbalance, and trips.

Having another load on the GFCI at the time the start switch opens may reduce the effects, preventing the trip of the GFCI.

Regards, Rod.

[Mike Henderson]

When you say the compressor doesn't work, is that because the GFCI trips? Or does the compressor just not start without tripping the GFCI?

In any case, if the problem only happens with that particular GFCI outlet, I'd suspect that GFCI controller. If you can plug the compressor into a different GFCI controlled outlet (controlled by a different GFCI device) and it works, that would be fairly conclusive proof that the problem is that particular GFCI device. It could be that the GFCI device is not wired correctly and that should be checked before replacing it.

Mike

[Wade Lippman]

I should say that I replaced the GFCI and all is well, but it is much simpler than that.

The vacuum turns on with a switch; the outlet doesn't have power until it is turned on.

I am truly sorry for bothering you with this.