Diy Inductor help needed

  1. Jmh474 New Member

    UK - Cambridge - Wisbech
    So I'm in the middle of modding a auto jack mig 130 (flux core welder), I plan on posting a thread when it's complete.

    So I'll a little lost on the build for the inductor, iv done a lot of research into the matter and confused on how to go ahead with the build.

    On cable size, from what iv read there are 3 options,

    1 - have half the size of the of the secondary side of the transformer.
    2 - the same size of the secondary
    3 - the same size as the welder cable used for internal connections

    I'm going to be using E's and I's and use a plastic shim to separate them to help reduce saturation of the core.

    What are people's thoughts on this thanks
  2. HughF

    HughF Member

    Work: Dorchester, Workshop: Corfe Castle, Wife's place: Frome
    get a scrap inductor out of an old welder and use that?I'll go back to I'll go back to
  3. eddie49 Member

    I think that for welding thin metal at low amps you need a high inductance. I would guess a laminated core about 4 inches square and 2 inches thick, stuffed with as many turns of 6mm2 as will fit, with a 1mm air gap between the E's and the I's will do the job. However, at higher currents the wire may get warm and the core may saturate, so it may need 10mm2 with a 2mm air gap.
    Jmh474 and HughF like this.
  4. LewisT Member

    central scotland
    I found this not to be true at least on wafer thin metal on a saxo with an inverter welder, my set has a dial for inductance and it was turned to max and despite being dialed down to 15a on current i was blowing holes in thin sheet the second the arc established, anything online i could find online about inductance said lower values for thin sheet.
    eddie49 likes this.
  5. eddie49 Member

    Yes, you are right:


    "The inductance setting on a mig welder controls the rate of current rise following the short-circuit state. That is during the time when the wire is short circuiting into the weld puddle.
    This setting affects the arc time too. That is the amount of time the short circuit cycle spends arcing and providing heat to the puddle.

    That is why adjusting the inductance makes the arc sound entirely different. A high inductance setting increases the time of each individual arc cycle and therefore can improve wetting of the puddle.
    A low inductance increases the frequency of each short circuit/arc cycle and can be useful for pinpointing a narrow bead in some joints.

    What this means to most folks is HIGH inductance is good for thicker metals where good wetting at the toes of the weld is a priority….and LOW inductance works better on thin metal."