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Modified sine wave inverter to power millermatic 211?

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  • Modified sine wave inverter to power millermatic 211?

    I am new to the forum, and new to welding. I just received my MillerMatic 211 welder.

    I asked this question to Miller tech 10 days ago, and received no replies.

    Can a MM 211 be powered from a modified sine wave inveter?

    I know how to do the load calculations, I am not asking about how to build a battery bank, or size the wire. I am asking if the electronics in a MM 211 will freak out with a Modified sine wave. I have read other similar threads.

    I know one can weld with 3 batteries wired in series, or with a 12 volt readywelder, or even use a special welding alternator and weld box. I am not asking about that.

    I have a Wagan 3000 watt running/ 6000 watt peak modified sine wave inverter installed in my truck. I also have a 20 amp gfci 120 volt receptacle hardwired to the inverter on the rear of my truck. I have used this inverter to run grinders, drills, chop saws, table saws, skillsaws, coffee makers, and task lighting. It works great. I have less than 6 feet of 0000 (4 ought) cable feeding the inverter from the battery bank. I also have a high output alternator.

    I do not expect to be welding bridges with this setup. 16 guage to 1/8 inch steel quick repairs.

    I do have a nice big and heavy generator that will run the welder for heavy jobs. 90% of the time The welder will be used from grid power.

    I don't mind risking letting the smoke out of the inverter, however i would be extremely upset if I let the smoke out of my new welder.

    Can a MillerMatic 211 be powered from a modified sine wave inverter?
    Can a MultiMatic 200 or other inverter based welder be powered from a modified sine wave inverter?

  • #2
    Miller tech stepped up and answered this question for me.

    The short answer is yes, a modified sine wave inverter can provide power to the welder. Miller reccomends an output of 3500 watts or more, so my inverter may be a little underpowered. I may give it the fire test just to see what happens.

    Cheers and happy new years


    • #3
      Problem with inverter generators is that they are not looking to put out instant amperage. They kinda prefer a slower ramp up, not say 1 amp at idle to an imediate 20 amp+ when you strike an arc. Soooo, ya takes your chances on smoken the input inverter.

      And the welder isn't looking for a slow ramp up, so that poses an equal problem


      • #4
        Just to be sure we are on the same page, I am talking about an inverter that converts dc 12 volts to ac 120 volts. Not an actual inverter generator like a Honda eu2000i. Some folks use the terms inverters and generators interchangeably. I would not consider my inverter a generator, nor would I consider my 7000 watt kohler generator an inverter.

        Thanks for the reply. I haven't tried welding with the inverter power yet. I would like to try just for giggles. Although I do not want to let the smoke out of the inverter, I would rather know if it will work now than during an emergency when the inverter may be needed for running other loads.


        • #5
          Well and engine powered inverter generator is merely an engine supplying say 42 Vdc to a converter inverter. Yours is powered off a bunch of batterys and some sort of charge voltage to them. You'll notice that when you power a drill, there is a slight ramp up. This is to protect the circuitry in the converter as it sences a load to be regulated. Now a modified sine wave unit is quite cheap. A true sinewave unit would be better but are extremely pricey. They will ramp up as well but are significantly better on technical electronics.

          Moral to the story, is that I wouldn't do it

          If Miller says its ok, I would get it in writing so your covered.


          • #6
            Just tried it on some 16 guage channel iron. It was a little slow to strike the arc, but once it got going, it butt welded the 2 channels together just fine. Not as good as plugging into utility power for sure. It may be effective on quick field repairs of thin material. Probably not hot enough to weld a spring perch to an axle housing, but enough to weld a support rod to a fender.

            Thanks cruzier for your explanation. I could see how extended weld time could smoke the inverter.

            Bottom line it can be done... For how long, that is anybody's guess. I will plan on using a heavy duty generator or utility power. The inverter just doesn't seem an ideal setup.