Lathe Moving Dolly

[Robsmith]

I have a similar problem. Motor and capacitors were tested by a motor shop, tested good. Problem was GFI pops when trying to start lathe, breaker does not pop. Broke the start switch trying to re-install it. Buy new switch, hire electrician. He worked for at least two hours , either the forward/ reverse switch is bad or the motor. Ordered new switch this afternoon.
No way in hades I'm going to move the lathe out of the shop. Just to remove the motor I had to raise the lathe with my shop crane. Bottom bolts on motor frame can not be accessed unless the lathe is at least 6" high so a wrench can turn.
While I'm waiting for the switch to arrive I decide to put the belts back on. The cogged timing belt is tough to install. Grizzly says in their manual to loosen the motor bolts, raise the motor and install timing belt. I did not want to raise the lathe again as it involved too much work. Backsplash, motor cover, and digital readouts have to be removed first. Instead I removed the upper pulley which is bolted to a steel plate I refer to as a banjo. The pulley shaft goes in a slotted hole, all I need to do is lengthen the slot so the pulley distance between the upper and lower cog wheels is a bit shorter . Probably will make the slot 1/2" longer. When I re-install the pulley will be set back to center of the slot giving me about 1/4" deflection.
Hopefully the switch is the problem or I will have to remove the motor again.
mike

Retired eleco here.. Clothes irons were well known to trip GFi's. Nothing wrong with the iron after one of those "special technicians" tested them . Still tripping. I had a look and there was fine lint in the lead connection compartment. ( terminal box) . Blew it out with air and no more problem. Have a look in all of your terminal boxes.

 

[BillC]

All's well that ends well! Happy for you and your success... My wife has the same unique ability to find what I can't in my mess of a shop with too many projects going at the same time. I'll get frustrated and walk in the house, then a few minutes later she will walk in with the lost item in her hand - "Is this what you're looking for?"
Strange; entering a conversation here will get a reply that I need counseling. I appreciate that advice... best thing to do is stay away from this place!
BillC

 

[RonW]

Been there! done that! got the bloody T shirt!! Just like everyone of us.
RonW

 

[L98fiero]

After searching for 20 minutes, I did what I always do in a situation like this.---I called my wife.

Annoying, isn't it, you spend a half hour looking for something and when you've nearly given up your wife comes in and in a few minutes finds the item where you put it so you wouldn't lose it?

 

[packrat]

That is funny My wife has the same unique ability to find stuff...do not know why that is..??

 

[Bill Lawson]

Brian, I seen to have the same problem locating misplaced things. I never realized that I was forgetful.
Bill

 

[werowance]

Everything was going back together perfectly, until I discovered I had lost my nuts!! Maybe a note of explanation is required--the lathe is held to the splash pan and the cabinets below it by six M12 bolts, and the nuts go on the inside of the cabinets. I distinctly remember putting the nuts and a couple of handles "somewhere", but damned if I could remember where. After searching for 20 minutes, I did what I always do in a situation like this.---I called my wife. Now I realize that this conversation could go off on a tangent here, but when I can't find things, my wife usually can. She searched for 10 minutes, and then as I walked by some engine display shelves in my office I spied a Tetley Tea container she gave me a couple of weeks ago to "keep little parts in". I picked it up, took off the lid, and sure enough---There were my nuts. Just her being in the same room as I am seems to help find things. Now, with my nuts happily found, I am too tired to do anymore tonight. I have to go tomorrow morning and pick up a grandchild for a visit with us. (We have to visit them in rotation because of this horrible Covid stuff.) After I have visited 9 year old Brennen for a while and made a run to the dump with a cubic yard of swarf, I will finish putting things back together and proceed where I left off on my Stephensons Rocket.

lol, everyone says my wife keeps my nuts in her purse.

 

[kwoodhands]

Retired eleco here.. Clothes irons were well known to trip GFi's. Nothing wrong with the iron after one of those "special technicians" tested them . Still tripping. I had a look and there was fine lint in the lead connection compartment. ( terminal box) . Blew it out with air and no more problem. Have a look in all of your terminal boxes.

Electrician came over Monday afternoon. He installed the new start switch, tripped the GFI again. He tested almost everything. It appears to him that their is an intermittent short in the forward/ reverse switch. Ordered new switch. He also ran an extension cord into the house on a non- GFI outlet . Motor tuned a couple of times and tripped the breaker. All the terminal boxes etc . tested good, capacitors also good.
Hopefully the new switch fixes the problem. At first he thought it was the motor. I told him where I took the motor to be tested as I originally thought the short was there. He has complete confidence in this establishment so the forward/reverse switch is the only thing left.
mike

 

[jwills8606]

I'm new here, but I gather this is mostly a UK or European forum, so the electrical system there is likely considerably different from the US. Nonetheless, GFCIs here work on a very simple principle: measure the current in each leg of the power wire, and if it's not equal, then there is a leak somewhere (possibly through the user!). (Of course, they also trip with overcurrent, like a regular breaker.) The GFCI part doesn't trip with shorts, but the breaker does, and you can tell which it is by whether the red button is in the tripped position. My guess, if it's the GFCI, is that there is a break in insulation somewhere - usually in a motor winding on older machines - that is letting a small leakage current through to the frame. These machines are fairly simple electrically, and if you have a good meter, you might try disconnecting both power leads AT THE MOTOR and measuring resistance from each to the motor frame. It should be near-infinite. I would say anything less than about 50k Ohms would be suspect.

Just a shot in the dark, but if the power source/switch/wiring beyond the on-off switch is new/good, then there's not a lot left.

 

[willray]

... if you have a good meter, you might try disconnecting both power leads AT THE MOTOR and measuring resistance from each to the motor frame. It should be near-infinite. I would say anything less than about 50k Ohms would be suspect...

Anything less than Megaohms is suspect, and it needs to be measured at operating voltage or higher to be useful for qualifying the motor insulation. Typical ohmmeters/multimeters are inadequate to the task. The job requires a device that is colloquially known as a "Megger" (though like Kleenex, there is actually a Megger that is literally named Megger also).

That being said, if we don't yet know whether the lathe/motor _ever_ worked on that GFI circuit, there's a 95% chance that we're still chasing ghosts here. Even if it _did_ work on that GFI before, GFIs go bad quite easily. Nuisance GFI trips are ridiculously common.

If your electrician was worth half his salt, he could have bypassed the switch and verified whether the GFI tripped with the switch out of the picture. Additionally diagnostic, if you can isolate the motor from everything else - separate it from the rest of the late and put it on a nice dry piece of wood - you can try starting it on the GFI circuit with the ground disconnected. A GFCI device's primary mode of operation is detecting imbalance between the current "going into" a device on one current-carrying-conductor, and the current "coming out" of the device on the other current-carrying-conductor. They don't need the ground hooked up to detect this. If you isolate the device such that the wires are the /only/ paths into and out of the device, and the GFCI still trips, it's tripping _solely_ because inductive loads _naturally_ generate situations that look like current imbalances that have nothing whatsoever to do with actual ground faults.

 

[awake]

lol, everyone says my wife keeps my nuts in her purse.

Errr ... that sounds rather painful!

 

[kwoodhands]

Electrician came over Monday afternoon. He installed the new start switch, tripped the GFI again. He tested almost everything. It appears to him that their is an intermittent short in the forward/ reverse switch. Ordered new switch. He also ran an extension cord into the house on a non- GFI outlet . Motor tuned a couple of times and tripped the breaker. All the terminal boxes etc . tested good, capacitors also good.
Hopefully the new switch fixes the problem. At first he thought it was the motor. I told him where I took the motor to be tested as I originally thought the short was there. He has complete confidence in this establishment so the forward/reverse switch is the only thing left.
mike

Anything less than Megaohms is suspect, and it needs to be measured at operating voltage or higher to be useful for qualifying the motor insulation. Typical ohmmeters/multimeters are inadequate to the task. The job requires a device that is colloquially known as a "Megger" (though like Kleenex, there is actually a Megger that is literally named Megger also).

That being said, if we don't yet know whether the lathe/motor _ever_ worked on that GFI circuit, there's a 95% chance that we're still chasing ghosts here. Even if it _did_ work on that GFI before, GFIs go bad quite easily. Nuisance GFI trips are ridiculously common.

If your electrician was worth half his salt, he could have bypassed the switch and verified whether the GFI tripped with the switch out of the picture. Additionally diagnostic, if you can isolate the motor from everything else - separate it from the rest of the late and put it on a nice dry piece of wood - you can try starting it on the GFI circuit with the ground disconnected. A GFCI device's primary mode of operation is detecting imbalance between the current "going into" a device on one current-carrying-conductor, and the current "coming out" of the device on the other current-carrying-conductor. They don't need the ground hooked up to detect this. If you isolate the device such that the wires are the /only/ paths into and out of the device, and the GFCI still trips, it's tripping _solely_ because inductive loads _naturally_ generate situations that look like current imbalances that have nothing whatsoever to do with actual ground faults.

My electrician tried the motor on two different GFI's , shop is split with GFI on half the shop and a another GFI on the other half. Also tried on a non- GFI by running an extension cord from an outlet in the house. Motor worked perfectly for 15+ years on the GFI. .
I will post results when the new F/R switch is installed. Switch has been shipped, not received yet.
Probably will not post til at least Thursday as I will be getting a pacemaker on Wednesday afternoon.
mike

 

[willray]

My electrician tried the motor on two different GFI's , shop is split with GFI on half the shop and a another GFI on the other half. Also tried on a non- GFI by running an extension cord from an outlet in the house. Motor worked perfectly for 15+ years on the GFI. .

I guess that sounds like you're in the unlucky 5%. So many people chase equipment problems on GFI circuits when the real problem is the GFI detector/circuit-breaker itself.

The fact that you blew the breaker when plugged in to the house is, interesting... GFIs don't sense overcurrent. Your house circuit doesn't sense ground faults.

Did your house breaker pop while the motor was still spooling up, or after it had stabilized at-speed? If it popped after stabilizing at-speed, you can probably verify that there really is a ground fault by disconnecting the ground, and trying it from your non-GFI house circuit again.

If you try that and it _doesn't_ pop, then the house-breaker pop was (highly likely) due to a high-current short to the chassis, which was being drained by the ground. If it /still/ pops when you do that, you have something very weird going on. ... beware, if you try that and the breaker does not pop, the chassis is almost certainly live - do not touch!

 

[kwoodhands]

I did not make my post clear, the GFI
itself popped not the breaker in the house. The breakers in the shop never flipped . Only the GFI on the receptacle. There , are two separate GFI circuits in the shop. Both pop when the motor starts up. Same results on the non GFI coming from the house.
Have not received the F/R switch yet. I hope when it is installed it solves the problem.
You asked if the GFI popped when it was spooling up , yes. It also popped the GFI after the motor ran well for up to 30 seconds.
I will post again with results after the new switch is installed. Probably not til the end of next week .
I'll be out of commission for a couple of days for minor surgery.
mike

 

[willray]

I did not make my post clear, the GFI
itself popped not the breaker in the house. The breakers in the shop never flipped . Only the GFI on the receptacle. There , are two separate GFI circuits in the shop. Both pop when the motor starts up. Same results on the non GFI coming from the house...

You seem to have quite the mystery - especially if you're saying that the garage GFIs pop when you're running it on the non-GFI from the house!

Fingers crossed that replacing the switch solves the problem, but even if it doesn't, I'm sure this can be diagnosed and fixed. Invisible gremlins start to haunt things once much in the way of electronics is involved, but motors and switches are simple enough that they don't show much interest.

At the moment though, you have more important things to do!

I will post again with results after the new switch is installed. Probably not til the end of next week .
I'll be out of commission for a couple of days for minor surgery.

Best wishes for a speedy recovery!
Will

 

[packrat]

At work {I was doing HVAC-R} we had a large machine that was not running right, come to find out the neutral wire was loose that was all it was....
A boiler one time was doing syringe things come to find out the McDonnell Miller Mercury switch was loose on the mount turning the flame off and on,
it was driving me nuts... I am sure you will solves your problem..

 

[awake]

A boiler one time was doing syringe things ...

Ah, sad that is, when even the boilers are starting to use drugs ...

Okay, I know that was an auto-correct-strike intended to be "strange," but I couldn't resist!

 

[packrat]

Yes awake, Got to use spell check more.....

 

[awake]

Ironically, it is the "spell-check" technology that is causing the problem - or at least, I think auto-correct developed out of spell check. And in any case, as I routinely remind my students, spell check only makes sure the word is spelled correctly; it does nothing to ensure that it is the correct word.

 

[packrat]

Yes I think your right..Are you a teacher.?