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Welder question: voltage vs current control

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  • Welder question: voltage vs current control

    Most inverter welders are current controlled supplies right? Would there be any cases where voltage control would more desirable than current control?

  • #2
    yup, MIG
    Or so I'm told by my MIG welding mates.
    The ones that come over for a beer with all those holes in their overalls.
    I'll stick with TIG
    Just got my head together
    now my body's falling apart


    • #3
      By inverter, you probably mean TIG, yes?

      A TIG (and stick) welder has a constant current power supply.

      A MIG welder has a constant voltage power supply.

      So on a TIG machine, you set the amperage. On a MIG, you set the voltage (and wire speed).
      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


      • #4
        An inverter can be either a CC, a CV, or both.
        My Miller XMT 304 is an inverter machine- which refers to how it turns 220 volts AC into welding current- but its output is either CC or CV, depending on which switch you throw on the front panel.
        This means it is an excellent inverter mig welder, and also a great inverter Tig or stick welder.


        • #5
          Like said above. Mig is generally a CV process and Stick and Tig is usually a CC process.

          Generally speaking because Aluminum Mig often runs better in CC mode and you can TIG with CV.


          • #6
            Hrm, went reading with my brain thinking about power supplies and not welders. Still reading, but is constant voltage primarily used in MIG because the wire-feed motor voltage is pulled out of the same transformer as welding current?

            Off to find an inverter MIG schematic to stare and compare...


            • #7
              No, there are different arc characteristics with CV versus CC. On the small machines wire feed speed is a function of the output voltage to make setting the machine a little more foolproof. All of the larger machines have wire feed speed completely independent of the voltage of the machine, the exception of synergic feeders that automatically adjust wire feed based on feedback from the welder.

              For schematics for a machine that is an inverter with built in feeder you could look at a Millermatic Passport or 350.


              • #8

                There should be some help in the free down-loadable pdf files at the following site.

                There is some good reading here from beginner up-wards.