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odd occurrence

Posted: Tue Oct 08, 2019 3:11 pm
by wa2crk
Had an odd occurrence with the Power Pro yesterday. I sanded a few pen blanks square and did a few other jobs and when I tried to use my bench grinder it would not start. Checked the drill press, no start. Then I saw the red light on the GFCI outlet was on. I tried to reset it and it would not reset. I unplugged the PP which was turned off at the headstock switch, and the breaker was able to be reset. Plugged the PP back in with the main switch off and the breaker tripped. Unplugged the machine and ohmed out the plug and did not see reading that would cause the breaker to trip. I plugged the PP into another circuit that was also GFCI protected and the machine worked OK. Then plugged it back into the original plug and tripped the breaker. I left the machine deciding to inspect the wiring later. Later came, and I plugged the machine back into the original outlet and all things were normal. Have not checked further because I had to use the machine, but I plan to check the wiring later. I may change the GFCI outlet just in case it has gotten flakey.
Bill V

Re: odd occurrence

Posted: Tue Oct 08, 2019 3:50 pm
by Hobbyman2
this may or may not be a solution , it was a experience I had a few weeks ago in the kitchen circuit on the rental, the wife used a gfi outlet most of the afternoon cutting tile , went back the next morning and the gfi was tripped , unplugged the tile saw and it still wouldn't reset , went home and grabbed the tester , when I got back the outlet reset ? I replaced the stupid thing and everything is good .the tile saw checked out to be ok , it works fine on every gfci circuit she has used . if your PP works ok on other circuits I would start with the outlet . just my .02

Re: odd occurrence

Posted: Tue Oct 08, 2019 6:18 pm
by nuhobby
When I launched the first new-owners PowerPro publicly reported on this forum, the DIY that I got in September 2010 Labor Day weekend, I saw it would not run on my GFI's.
I recall even hooking up an ammeter and reporting a very tiny leakage current at that time; the number escapes me now. Anyway, I've always been running on a non-GFI outlet since then.

Re: odd occurrence

Posted: Tue Oct 08, 2019 6:50 pm
by JPG
I am curious how y'all checked the culprit(s).

Measuring leakage current is the only meaningful measurement to take(an ohmmeter will not detect 'the problem').

5 ma(ac) is the typical trip limit. The cause is typically due to capacitance in the filter. Yes resistance(leakage caused by moisture etc.) can also contribute.

Re: odd occurrence

Posted: Tue Oct 08, 2019 7:27 pm
by nuhobby
I found my old report from Sept 4, 2010 :)

Here goes:

Just got in a few minutes to check a measurement. The ground-lug current existing when the outlet trips is 2-3mA AC on my little DMM. Needless to say, I've found *no* resistance measurement anywhere near the expected 40-60kOhm leakage. I can't find leakage at all. I'll sit tight on this and hear how others do, before raising any flags. Boy, though, it is a Sweet machine.

Re: odd occurrence

Posted: Wed Oct 09, 2019 2:44 pm
by beeg
Power Pro's and cheap GFCI's not play well together. Get a medical grade GFCI.

Re: odd occurrence

Posted: Wed Oct 09, 2019 4:13 pm
by wa2crk
JPG
Yeah but the trip current exists for such a short period of time before the critter trips I gotta be real fast to measure. I did the resistance check to see if there might be a path caused by moisture that would cause a trip. Nothing detected.
Beeg and Nuhobby
The previous discussion as I recall was about GFCI's that tripped when the machines were in use but this one tripped when the machine was plugged in even though the power switch was in the off position. The 20 amp GFCI is in a box that is mounted in a concrete block wall, not surface mounted so a clean out may be required there.
Bill
PS, I will use a high quality hospital grade GFCI for the replacement.

Re: odd occurrence

Posted: Thu Oct 10, 2019 12:02 pm
by chapmanruss
The PowerPro Instructions state not to plug into a GFCI outlet. I have mine plugged in a regular outlet down stream of the GFCI plug on the circuit and no problems to date.

Re: odd occurrence

Posted: Thu Oct 10, 2019 7:25 pm
by jsburger
chapmanruss wrote:The PowerPro Instructions state not to plug into a GFCI outlet. I have mine plugged in a regular outlet down stream of the GFCI plug on the circuit and no problems to date.
Doesn't a GFCI protect all outlets down stream from it?

Re: odd occurrence

Posted: Thu Oct 10, 2019 9:00 pm
by Hobbyman2
Doesn't a GFCI protect all outlets down stream from it?

============

Only when wired in a series through the first plug , in other words you can use one gfci plug that will cover several plugs , but be warned , when one plug trips it can trip the one before it ,or even in some cases the first one in line.. or you can wire in a parallel circuit and only the plug in question would be covered .