Lhorn tells us....
Quote;" Since it's a true 220 application (ie the coil on the mag starter is 220 not 110), my understanding is that I dont need a neutral (the middle, L shaped prong on the dryer plug), just 2 hots and neutral. "
You don't need a neutral, buy only 2 hots and a neutral? Am I missing somthing here?
If you're using a three prong welder plug and receptacle you have two hots and a neutral.
How is your welder grounded? I think its not.
The trend is (and it may be code, now) to separate the neutral and ground. Dryer plugs and receptacles now have four prongs - two hots, a neutral and a ground.
Again, how is your welder grounded? My welder is on a 70 amp 220 breaker. I'd be more concerned about a properly grounded welder than a compressor that puts out air vs. electricity.
The best ground for a welder is a conductive rod in the ground that contacts the water table. That's about as rare as a muffler on a Harley. Just pounding a ground rod in doesn't mean you have a perfect ground. Though, better than nothing.