3 phase welder on rotary convert

[Kerry Pinkerton]

I have a chance to buy a big LINDE welder with MIG attachment. The Mig is standalone and can be mounted on a boom or left on top of the box. This is a transformer unit, not one of the new electronic things. I can get it cheap but it's 3 phase. I have 3phase on a rotary converter but seems like I remember hearing that you can't run a welder on a rotary converter?????

[bobadame]

Kerry, I've seen it done. I bought a lathe from an old guy who was running a big Miller mig welder on a home made 3 phase converter. He had a small 110 vac motor mounted an a hinge arrangement. The small motor had a rubber caster mounted on the shaft. He would start the small motor and then push the caster against the shaft of the 3 phase idler motor then he'd start the welder. It worked great for him.

[tsutt]

Kerry I ran a miller 3phase on a converter for several years, no problems. Todd

[metalchomper]

I'm in a similar situation. Is there a rule of thumb for horsepower vs welder size?

[alloyspec]

To size a converter, I think you could look at maximum amperage draw of the welder and size the converter for the same amperage motor. Maximum motor amperage is pretty easy to find in spec-sheets. Or call the converter maker. If I remember right mine has a maximum amperage draw sticker inside the box with the capaciters.
Alan

[Kerry Pinkerton]

The guy called me back yesterday and offered me the converter for $200 bucks. It's a 'store bought' unit and he think's its a 20hp. It was specifically for running the welder. I'll probably get it and the welder.

[Peter Miles]

That sounds like a heck of a bargain. Snap it up!