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  • Input power

    Just a quick input power question. I've got a MM251 set up for my home (230V single phase) and would like to use it at the shop as well. I got 600V three phase at the shop with transformers to give me 120/208 three phase in the main panel. Is it just a simple matter of using a 2 pole breaker in the panel and changing the jumper to 200V on the machine?


  • #2
    Get a licensed electrician for that. What he costs is less than replacing the machine you burned up.
    Lincoln: Eagle 10,000, Weld-Pak HD, Weld-Pak 155, AC-225, LN-25 wirefeeder
    Miller: Syncrowave 250DX Tigrunner
    Westinghouse: 400+ amp AC
    ThermalArc Handy wirefeeder
    1 Harris, 3 Victor O/A rigs
    Arcair gouger
    Too many other power toys to list.

    Do it right, do it once. And in all things ya get what ya pay for.


    • #3
      Your best bet is to follow Jolly Roger's advice.

      There is a chance you have 230v available in your shop, but perhaps not. It's not as simple as installing a 2 pole breaker. You might need a buck and boost transformer installed to get 230/240v single phase. It all depends on your service and installed panel.

      If you do connect your welder to 208v and it is not tapped for it, you will probably burn up the fan due to low voltage. Also, it will not perform as expected and could very likely ruin it and your day.

      Once again, and this is coming from someone that has been in the electrical business more than 30 years, get a licensed, qualified electrician to help you with this. I'm not advertizing for my trade, I'm just advising your safest route.


      • #4
        Thanks for the quick responses guys. I agree an electrician should be consulted however at this point I'm just trying to see if it is even possible. Like I said I've got 600V coming in and various transformers to feed my CNC machines and the main panel (fed by a 45KVA 600 primary, 120y/208 secondary transformer, 120 comes from line to neutral and 208 is from line to line) Pretty standard stuff, I wired my CNC's and their isolation transformers myself none of which go through the panel of course.
        Most of the breakers in the panel are of the 120 variety for outlets and some lighting in the office. Their is also one 3 pole breaker for the compressor and one 2 pole breaker which is not hooked up to anything. The machine is easily switchable between 200V(208V) and 230V simply by moving the jumper link on the machine. There is 208V at the breaker, I don't see why it shouldn't work fine, perhaps someone could explain why or why not.

        Thanks again,


        • #5
          Originally posted by 79Jimmy View Post
          ...Is it just a simple matter of using a 2 pole breaker in the panel and changing the jumper to 200V on the machine?
          If you have a 200V jumper for input power (which the standard MM251 does), then yes, it is that simple, assuming you are competant enough to install the circuit breaker and receptacle. Just remember to always change the jumper if you move the machine back and forth between locations.

          If you insist on wanting a licensed electrician, you can fly my wife and I there for the weekend. Pay the airfare and I'll do the job (labor) for free.
          Last edited by MAC702; 08-11-2007, 08:39 AM.