Jet Lathe Electrical issue

[Douglas Robinson]

I moved my lathe into my new shop and regardless of which outlet I plug it into, when I turn it on the breaker in the GFI goes off. Anyone have nay idea what is happening, or where the short might be?

 

[ScottM]

Doug what model Jet lathe?

 

[bowman]

Is it only the lathe that is tripping the GFCI? Does it trip with any other equipment plugged in?

 

[Douglas Robinson]

Just the lathe. It is not the wiring in the walls.

 

[pop-pop]

Hazarding a blind guess. First open the lathe’s switch box and look for something amiss. Often one of the slip-on connections will have worked itself out of position.

 

[Charlie]

I don't think you can use a VFD machine on a GFCI circuit.

 

[marinosr]

Yeah if you have a VFD you're going to need to put a low pass filter between the VFD and the lathe.

This explains why: http://acim.nidec.com/drives/kbelec...updated-using-vfds-on-gfci-devices.ashx?la=en

 

[Jeff]

Replace the GFCI outlet with a standard outlet. You may not have needed the GFCIs in your shop but some electricians install them anyway because they think that they're required in that shop environment by code. I had the same thing in my garage back in 1989.

 

[Douglas Robinson]

OK, I will try an extension cord to a non-GFI outlet and see what happens.

 

[Hmerkle]

OK, I will try an extension cord to a non-GFI outlet and see what happens.

Doug,
Do you need to borrow an extension cord? It seems like it is taking you a long time to find yours!

Seriously, did that work?

 

[mkepke]

Maybe its just a really, really long walk to find a non-GFCI outlet?

 

[djvanduy]

I don't have a Jet, but if I recall correctly I think I had a similar issue with my Nova several years back. I believe that it was caused by a bad fuse. There is an inline fuse in the headstock of a NOVA, so might want to make sure its not something simple like that if the JET has one of those. Good Luck

JVD
www.vanduynwoodwork.com

 

[Douglas Robinson]

It is NOT the lathe. I ran an extension cord to a non GFI outlet and everything worked fine.

 

[Hmerkle]

Thanks Doug!
We have been waiting a long time for the solution!

 

[FlyingRon]

That article has a lot of errors in it. I can't tell if they're dumbing it down for their expected audience or whether they are really clueless about GFCI design. The fundamental truth is however that VFDs as well as certain other motors can nuisance trip the GFCI.

Unless your shop is in a place that mandates it (like in an unfinished basement or garage), I'd forgo the GFCIs. If you can't do that, one option is to either change it to 240 or hardwire it which obviates the need for GFCI as well.

 

[Oka]

Glad you found the issue. As a rule, Whenever you have an elec problem, best to run a continuity test. I apologize if you already know this -Make sure there are no transient grounding (bare connection or wire). Then, check your load on the line voltage. One basic rule that is important - starting loads will spike the elec draw roughly 125% of running demand. So, if you have a 10 amp motor, the start would draw 12.5-13 amps. If you have a 15 amp motor, you would draw on start 18.75-19 amps. There are not alot of GFI 20 amp circuts in homes..... like almost none. Almost all are 15 amps. Also,modern motors will have starters that are more touchy than in the past. Like others have stated, you really shouldn't run equip on a GFI. Just make sure you verify you have positive ground. GFI's were originally designed for extra protection where there is a possibility of wet conditions. Now-days it seems all the counties in the USA ask for them to better "idiot-proof" the elec outlets.......

Hope that helps.

 

[AllanD]

I had exactly the same problem when I moved my Robust lathe into my new shop. It uses a VFD and kept tripping the breaker. I changed the breaker to a regular one (with the blessing of my electrician friend) and now works fine

 

[Douglas Robinson]

Yes, I am pretty sure it is the breakers.

 

[FlyingRon]

All 120V 15/20A receptacles in certain areas are required to be GFCI. These areas include garages, unfinished basements, and accessory structures at or below grade (among others). It's not legal, nor particularly safe to replace a 120V 15/20A receptacle that requires a GFCI just because you want to run a lathe there. I gave you the legal alternatives.

 

[Jeff]

All 120V 15/20A receptacles in certain areas are required to be GFCI. These areas include garages, unfinished basements, and accessory structures at or below grade (among others). It's not legal, nor particularly safe to replace a 120V 15/20A receptacle that requires a GFCI just because you want to run a lathe there. I gave you the legal alternatives.

Sometimes they aren't required. I have 2 refrigerator/freezers in the garage on a 20amp circuit. The electricians installed a GFCI but when the inspector came he told me that it wasn't needed because it's unlikely that the refrigerators would fall into the garage sink. He suggested that I remove the GFCI and use a regular duplex receptacle and he showed me the "exemptions/exceptions" in his code book. It wasn't illegal for me to change it. The other 12 receptacles in the garage are 4' above the floor, all are on a GFCI circuit and nowhere near the sink. I didn't ask the inspector if they were required but I haven't seen a need to change them after 30 years.