welding equipment

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rmonroe

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We have production wire welding equipment and I would like to know if we need an isolated grounding system.
 
No, but you might look into it for your more sensitive electronics. The benefits are debatable (especially around here!), but welding can create some strange currents.
 
Grounding rod

Grounding rod

What I mean by isolated ground is a grounding rod installed next to the welding equipment. We have a ABB Robot used with an welding application and sometimes we are experiencing problem with the control system.
 
You can drive as many rods as you like but they must still be bonded to the GEC.
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Take a look at 250.54 for Supplementary grounding electrodes.

What is being described by rmonroe is a supplementary grounding electrode.

Chris
 
Chris, I may have mis understood his clarification but it almost sounded like they were thinking of a seperate ground for the machine. If I'm wrong about that I'm sorry. But you are right about 250.54
 
Chris, I may have mis understood his clarification but it almost sounded like they were thinking of a seperate ground for the machine.
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Maybe I mis-understood what he was meaning. I was envisioning a ground rod installed at the welder and attached to the equipment grounding conductor.

rmonroe, are you connecting this ground rod to the equipment grounding conductor of the welder?

Chris
 
Studies by the Electric Power Reliability Institue document that installing a ground rod at a machine tool (or welder) actually create more problems, due to voltage gradients in the earth, this ground rod adds to the noise the machine sees.
As many 250.54 electrodes (supplementary,I call them time and materials electrodes) can be installed as you want. There is little evidence that they are effective. Just don't install a ground rod and isolate the machine tool from its supply equipment grounding conductor. Thats a code violation as there is no ground fault return path.
Have you considered a UPS on the control circuit? It could even be a problem with EMI radiated thru the air from welding. Seems like the welding machine manufacturer could assist you.But if they say install a ground rod, go to plan C
 
Three rods ten feet long and spaced in a triangle ten feet apart or what some call a ?Delta? ground.
Oh wait a minute, this is for an electrical fencing unit, I?m sorry, I was a little confused for a minute.
Well okay then I was a lot confused from birth for those of you who are going to jump on me about it.
 
welder ground

welder ground

Sorry I could not respond sooner but was caught-out on some equipment issues.

We have two ABB Robots in a work cell for a welding application. I am not directly involved with this equipment but I do know that they are experiencing problems with the controls and servo drive issues. It was recommended that they install an isolated grounding rod next to the frame of the welders and ground them to the rod (machine ground conductor would not be attached).

I do not think that this would be a safety method do to the fact that you could have a potential difference between building ground and the new isolated ground
 
rmonroe said:
It was recommended that they install an isolated grounding rod next to the frame of the welders and ground them to the rod (machine ground conductor would not be attached).
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It would seem impossible to isolate the frame of the welder from its ground (unless you're referring to the welding negative.)
 
grounding welders

grounding welders

It has been decided to contact both ABB (supplier of the robot) and the supplier of the welding equipment for there recommendations.

SAFETY IS FIRST

Thanks for your input...

rmonroe
 
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