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ac welder conversion

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  • #16
    I will guess that Miller limits the DC output of the Thunderbolt so as not to kill the transformer. If you pull more output from the system, even if your components are up to the task, the rest of the components may not be.
    Where are you? Maybe someone can put you onto a local deal. Try for craigslist searches and look at Kijiji if you are in a place listed by them to find an actual Mig machine. You will be much happier. Or do the conversion for the learning experience and have fun. Just don't expect miracles.


    • #17
      meltedmetal i sure do not expect miracles from this setup, at least i woukd be able to run 1/8 7018 dcep no problem. for the feeder part i know i would be best served with some CC-CV inverter type machines. the only thing is that i only have 1ph 220v in the shop. im planning on buying one in the next year but i have to wait for a busier time of the year since almost everything is dead here during the winter. it is more an experiment than trying to do something sturdy to weld 60hrs a week with it. could be fun. worst case scenario ill fit the rectifier in my dad's thumbstone 225ac


      • #18
        If your set on trying it this is how I'd do it.

        Use the Bridge Rectifier from a Delco AD244 alternator.
        When I build on board welders I use the them. If you use these ones from the link below you should have more then enough for 150 amps. Plus you can use the back of a AD case for a sink. The bridge mounts right into it and a $2 small personal fan from Walmart blowing through the case will keep it quite cool.

        Your going to also need a toroid core. The capacitor will overheat without it. All the capacitor does is keep the pulsing D.C. from working like AC.

        If if you go with used junkyard parts costs could be even less

        T25XHD Extreme Heavy Duty Bridge Rectifier For Delco & Delphi AD237, AD244 Series Alternators. 210 amp rated.
        Last edited by Lostone; 12-25-2016, 11:18 AM.


        • #19
          TC-150, that's it! I have one on my thunderbolt. It's rated output is 150amps and it doesn't have much room for excess. There is. Fusible link inside the machine that will blow. They're cheap, just not readily available. Took my local industrial electrical parts house about two days to get some for me. <br />
          <br />
          I was doing some scratch tig and pushed my thunderbolt to the max...about five minutes of welding and the rectifier just shut off. Sometimes I do dumb stuff.