Welder power problem?

[cornbread]

Newbie here. I'm not a welder but an electrcian. Our welding guys are telling me they are having problems with a 480 volt welder at one of our fab shops. It's pulling the bead to one side. I can take the same welder to another fabshop and it works fine. I suspected grounding may be an issue. In thinking about it a bit more I don't see how grounding would be the problem as the welder is supplied with only 3phase 480 Volt. Has any one experienced such an occurance? Any clues as to where to look would be greatly appreciated!

[duaneb55]

Welcome to the forum cornbread.

Dropped a phase?

Bead favors side toward or away from work ground?

Machine details?

[specter]

After you flip off the main power try checking all your power connections (wiring nuts) and connections in the main power panel. Sounds like one of your wires may have come loose.

[cornbread]

More data. The welders are Miller SRH-444. In talking to one of the welders he said the welder worked well until a month ot two ago. He also stated the problem does not happen until they are well into a weld. On my side of thsing I checked the incomming power and found the following:

Approx 490 phase to phase
A to ground was 247
B to ground was 427
C to ground was 247

Look like a delta with one winding center tapped to ground. I have a call into the miller folks to see what the input power specs are.