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  1. #1
    Join Date
    Nov 2009
    Maryland's Eastern Shore

    Default I need help changing polarity on MIG welder

    I rescued an Airco Dip-PAK 200 from the dumpster a while ago and it runs great. I wanted to stop using gas shielding, and switch to flux core wire. I have no owners manual only a schematic, yes i know how to change the polarity at the studs, just flip the + and -, but once I took the covers off it looks like a pain in the ass, (have to make 2 jumpers 18"-24" long out of 2/0 crimp the ends then run the wire in that tight space.)

    Looking at the drawing, and in side the unit it would be easier (for me) to just flip the 2 wires on the output of the rectifier, but this is where my question comes in, can I just switch the 2 wires on the (+ and -) output or will this have an effect on the capacitors, and what I'm guessing is a choke coil?

    I guess they did not intend to weld flux core with this machine and rather than burn it up I would like to make sure that it will be ok to make the polarity change, or sell it and get a MIG/ flux-core capable machine.
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  2. #2
    Join Date
    Apr 2010


    I bought a old Snap-On YA-218, that had been used at a body shop, and used it as a MIG unit for many years. I changed it over before I sold it as the new owner wanted to use it only for flux core. Had to open it all up and just switched the pos. and neg. and it worked great. While you are in there you might want to install a two sets of the smallest tweeco fittings on short leads and run them on a convienent area outside the unit so that you can change the polarity back and forth without having to open it up again. Hope this helps. Mike

  3. #3
    Join Date
    May 2009
    Central North Carolina


    You do NOT want to change the polarity at the rectifier. Doing this will damage the capacitors. Change the polarity at the output, even if it isn't as convenient. It's easier to do on newer MIG welders than some of the older ones. I guess they didn't think anyone would want to do this when they designed some of the older ones. I'm not familiar with your machine, but the schematic that you provided makes it obvious.

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