Welding Problem

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I have the following problem when welding large railway cars. The cars are connected to a rotator which moves the car 360 degrees. The rotator is powered by a motor which is 3 phase and fed by #10 conductors. The EGC is also #10. When I clamp my welding ground cable to the frame of the car and begin to weld, the #10 EGC is burning up. Any suggestions why and how to correct it?

Thanks!
 
My first guess is that the #10 EGC has less reistance back to the generator's 'ground' terminal than the clamp and cable have. This is similar to a service with an open neutral and the GEC is carrying the neutral current.

You need to find either where the #10 is improperly connected to the gnereator's ground terminal, or where the ground clamp and cable has an improper open (presuming at least one of these is improper to begin with.)
 
Is your work clamp run directly from the car to the welder or is it grounded to something else as well?
...or instead. Good point, Bob. Maybe he's clamping onto the rotator, and not the car frame.

I wonder if he could draw an arc with the ground clamp disconnected, and shouldn't be able to.
 
Larry neither the work or electrode lead of a welder should be connected to ground (other then at the work piece) or branch circuit EGCs will be melting on a regular basis. :smile: (Reponse to Larry's first post)
 
as they said above, if you're going to use the #10 as your ground lead you are going to burn it up every time. if you are using an electric arc welder and you aren't using the ground as your welding return lead, then you might wanna have the welder checked out.
 
It might help if we stopped calling the 'work' lead ground as that adds to confusion of it's purpose and function.:smile:
 
Larry neither the work or electrode lead of a welder should be connected to ground (other then at the work piece) or branch circuit EGCs will be melting on a regular basis. :smile:

It might help if we stopped calling the 'work' lead ground as that adds to confusion of it's purpose and function.:smile:
Believe it or not, I originally typed up my response using "work" but changed it to reflect the OP's word use. Notice the quotes around mu first use of "ground."
 
as they said above, if you're going to use the #10 as your ground lead you are going to burn it up every time. if you are using an electric arc welder and you aren't using the ground as your welding return lead, then you might wanna have the welder checked out.
I believe he doesn't want to use the #10, but somehow is. That's the basis for the question.
 
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