Kemppi Super kempomat 150 mig welder power problem

  1. Thor H New Member

    Reykjavik Iceland
    Hi everyone. I just joined so please be gentle with me...

    I have an old Kemppi Super kempomat 150 mig welder that has a problem with the power no matter what power setting the machine is set on it has a very weak arc so weak that it almost doesn't melt the wire.

    I saw someone talk about this for a long time ago that this might be something about „the heatsink and the the so called polarity screw“

    Well, the problem is, I don't know what it means, That is, the heatsink and the so called polarity screw and where it is located in the machine

    Please excuse my English language and writing

    With kindness and hope.


    P.S. I also include pictures to explain what I am looking for.
    • 20190410_201325.jpg
    • 20190410_201402.jpg
  2. eddie49 Member

    Hello, and welcome to the Forum.
    Regarding the so-called "polarity screw" : the machine may be adaptable to gasless wire, which would involve making the torch negative ( normal solid wire with gas = torch positive, earth clamp negative ). This change of polarity is often done by moving wires or links on bolted connections. Make sure that ALL connections in the whole machine are clean, tight, and not corroded or burnt. These checks include both ends of the earth cable and clamp.
    Then measure the AC voltage of the secondary of the main transformer, across the rectifier input - this should be about 20 to 30v AC.
    Check the DC output voltage from the torch tip to the earth clamp, at each power setting. This should range from low power 16v up to maybe 35v at the highest power setting.
    Last edited: Apr 12, 2019
    Thor H likes this.