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3 Phase Welding

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  • 3 Phase Welding


    Just wondering what determines the 3 phase welding arc and what engine drives in the Miller line have 3 phase welding arc??

  • #2
    Good question!

    What determines the 3 or single phase arc is what type of weld generator (alternator) is used to supple power to the weld rectifier. The rectifier changes the AC to DC to weld with and if you supply the rectifier with 3 phase AC it will give you smoother DC out the rectifier.
    It is a noticable difference in spatter and control. Most of MILLERs larger engine drives are 3 phase along with the smaller Trailblazer Series. The Bobcat series is a single phase weld output as well as the Blue Star 3500 and 6000. The Bobcat 3 phase is a 3 phase AUX POWER welder but still a single phase weld output. I have the Trailblazer as well as many others that participate on this site and I think it has a great weld performance. One other thing. The 3 phase/single phase only refers to the DC welding circuit. The AC weld output is still single phase. The Trailblazer's AC runs at a higher frequency than other units in the same catagory which gives it great arc control when Tigging. I'm sure others can give an opinion too.

    Hope this helps.



    • #3

      So then, it is true that a 3 phase xfmr welder will have a smoother arc than a single phase machine? I have a Dial Arc 250 and the only way I can describe it is rough. It is a constant struggle to control the arc. Now, my XMT304, this machine is a dream.
      I used to use Big 40's on constuction years ago and they were a dream to weld with. This Dialarc, perhaps there is something wrong with it. I just always put it down to single phase power. What do you think?



      • #4

        There may not necessarily be something wrong with your Dial Arc. The CWI who did my last tests put me in front of an old Dial Arc 250. To say the least I was lucky to pass. The machine gave me fits-especially on the 6010's. I think his building has a lot of power fluctuation. I had to re -adjust the current between rods many times.

        My experience with the Dial Arc was not a favorable one. However, the machine was old and probably not well maintained. Perhaps your machine just needs to be gone through an checked out. Two of my local Miller dealers offer such services.

        The Dial Arc 250 never will have an arc like the Big 40 or the XMT. I have used all these machines and must say the XMT is one of my favorite shop and in plant machines. The Big 40 also runs a nice arc. I understand there have been a number of changes to the Big 40 cc/cv deluxe model for this year. I am looking forward to using one if presented with the opportunity.


        • #5

          You are comparing three different animals here.
          The XMT is an inverter machine and is not at all fair to compare its arc to that of a 60HZ transformer machine like the Dial Arc 250. My XMT ran well on single and 3 phase input power. However, I am thinking the arc output remained the same except for the amount of welding current available.

          The Big 40 has a very large armature in its generator and produces a nice 3 phase arc output. However, the Trailblazer Andy mentioned performs as well as anything out there in terms of a good, clean, 3 phase DC arc output. Maybe you will run across one sometime. Don't pass up the opportunity to try it. It's AC arc runs at 120 HZ and makes tigging an engine drive dream.