Help me Make my GCFI Stop Tripping

[Ulma Doctor]

i don't recommend this for the faint of heart...
i had a similar issue with machinery tripping the GFIC, so i removed the GFIC outlet, replaced it with a NON-GFIC outlet, and went back to work.
(some technology is worthless no matter how safe it is)

 

[hman]

Intermittent/unreproducible problems are the ABSOLUTE WORST!!!!

 

[gerritv]

Intermittent/unreproducible problems are the ABSOLUTE WORST!!!!

Which is why some of us where strongly recommending checking the electrics now, before the next item on the list. Now that something has changed who knows when this will come back. I learned my lesson when working for Univac in the 60's- early 80's on mainframes spread across 3 floors. Change one thing at a time, if nothing changes put that back. Then on to next thing to try. Too often if nothing changed, you might have added a new problem masked by the original.

 

[stupoty]

I think this thread may be annoying some people, and I'm afraid I'm here to make it worse. The motor has started working for no discernible reason. It starts with the belt attached, and I even started it while applying pressure to the pulley to make the motor work harder.

I have done nothing to the motor since the last time it popped the GFCI, except for adding oil to the cups. I don't see how this could matter.

The bearing on the wheel end is no good. I can confirm that. It gets too hot to hold onto after a few minutes. The other bearing stays cool. I don't know how bad things are. I have not measured the RPM's yet to see if the bearings are slowing the motor down.

I had never seen this type of motor before, so I thought it was pretty fancy. I have since learned that 1/4-HP 1725-RPM motors with rubber mounts are very common. TEFC jobs cost around twice as much, however, so I'm glad I don't have to buy one right now.

I have been trying to open the spindle with a pin wrench, but it's not going well. The slots are getting chewed up. I drilled two new holes for the pins. I could get a better grip on the nut if the inner spanner nut were out, so I'm going to see if I can remove it. I am hoping there is no shoulder trapping it under the big nut. I'm off to the auto parts store to buy two 1/2-20 nuts so I can grind them down and turn them into jam nuts for immobilizing the spindle.

mostly everyone hear like a mystery

The oil might have been all caked up and acting like glue , a little bit of warmth and manipulation might have loosened it up a bit.

With regard to the pin spanner ring, use a pick type implement and/or wooden sticks , to clear out all gunk you can and double check for set screws and such , I honestly haven't ever forced something open to find there was a set screw making a nice burr on some moderately important part, no no never happened (goes to corner from shame)



Stu

 

[Chips O'Toole]

I got it apart. I had to make a tool. The bearings have something exactly like cosmoline on them. There are two bearings on the front end, mashed against each other. I haven't checked the rear bearing. The whole shaft assembly popped out in my hand unexpectedly, leaving the rear bearing in the machine. It appears to be a slip fit, which seems awfully odd to me.

There is no scoring or damage on anything, unless you count the marks I left on that infernal nut. I improved the design greatly.

I'm surprised a slip-fit bearing can run without chewing up a shaft.

Now I have to identify the bearings.

Too tired to post photos right now.

 

[Cadillac]

Without any pictures you not gonna get any definite answers. Having a double bearing in the front sounds like you have angular contact bearings in the front ,the rear bearing is gonna be a slip fit for expansion so the spindle doesn't bind up. I would doubt there is cosmoline in the spindle housing dried up grease or oil yes cosmoline no. The front bearing set is there a locknut holding the two bearings on the spindle? When you get some time take some detailed pictures and post it'll be the best way to get some accurate advice.

 

[7635tools]

It is a ground fault circuit, so check between hot and ground, and neutral and ground. One of those is where the fault is in the motor. Unless it is the outlet of course. You check between hot and neutral only means your windings are ok. Lastly, make sure that the ground/frame is also connected to the power connector. GFCI's need all 3 wires, e.g. did someone cut the ground prong off?

And of course try running something else on that circuit to see if it blows as well.

GFCI’s do not need a ground wire hooked up to it to function properly. It senses the current imbalance between hot and neutral.


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[gerritv]

Typically spindles retain only bearings on one end, the other is free to float to compensate for expansion due to heat build up.

 

[gerritv]

GFCI’s do not need a ground wire hooked up to it to function properly. It senses the current imbalance between hot and neutral.


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Yes you are right, but given the other issues I would be checking the wiring. If the GFCI is tripping, then I would want a proper ground as well. Without verifying it might look like things are ok but they might not be.

 

[Asm109]

Typically spindles retain only bearings on one end, the other is free to float to compensate for expansion due to heat build up.

This is very true. Bearing makers also want the rotating ring of the bearing to be a press fit. Avoids fretting corrosion that way.

So the upper bearing should be press fit to the shaft and floating on the OD in the housing. That is bearing best practice, doesn't mean the designer of this machine followed them.