View Full Version : TIG interference w/PWM controller

09-13-2007, 08:20 AM
I'm thinking of building a small, variable speed rotating jig platform for a precision welding base. The speed controller will be the table feed controller from my mini-mill. This is a solid state PWM controller that I plan to couple with a small gear, belt, or chain drive linkage. My question is since this needs to sit on my welding table and the weld part will be "in circuit", will the TIG cause EM interference and trash the PWM controller?

Thanks, Cadwiz

09-13-2007, 10:13 AM
At my shop I modified a rotary table with a feed from a mill to rotate parts for welding. It worked great. But we only did MIG welding on it. The part of the weld arc that may cause trouble would be the "high frequency" used for AC welding and starting the arc on DC welding. We have blamed that for frying a calculator and a digital caliper left on the weld table. I always take my cell phone out of my pocket when welding, just to be sure.
It you decide to try it, make sure everthing is well grounded.
Good luck, Paul

09-13-2007, 12:44 PM
You'll want to isolate the motor/controller from the table. A belt or coupling with a phenolic bushing will provide part of that, but you need to make sure that the motor mount is isolated from the frame of the table. I used to work on high speed welding machines and all servo motors were isolated from the frame with phenolic material and special coated bolts and phenolic washers. Pay attention to the mounting bolts and use nylon if possible. Make sure you have a very good ground bewteen the welder supply and the table or the current will seek another path, which may go through the controller.