TIG welder

Discussion in 'The Projects Forum' started by kubeek, Dec 12, 2017.

  1. kubeek

    Thread Starter Expert

    Sep 20, 2005
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    I am planning to bulid my own TIG welder, somewhere in the order of 120-160A output. I want to use this Czech project as the basis of my design, hopefully with some imporvements of my own.

    After the basic DC source is done, I plan to add an AC switcher to allow welding aluminium, and a HF start circuit. The price goal for the DC source parts is around 250€ (not counting components destroyed in development ;) ) but that might be wishful thinking.
     
  2. bertus

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    Apr 5, 2008
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  3. kubeek

    Thread Starter Expert

    Sep 20, 2005
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    The first thing I want to improve on is the transformer, which by my calculations seems inadequate. The original uses an E70 gcore, with 18 turns of 64 x 0.3mm dia. wire (approx. 4.5mm2) and secondary of 2x 4 turns of 90 x 0.3mm dia (approx. 6.3mm2). The crossection of the secondary seems quite inadequate, and the number of turns prevents higher crossections.
    Because the cores are not very costly, I decided to use two E cores joined together, giving me double the core crossection and therefore half the number of turns for the same flux density. This will require a custom bobbin, but it seems to be better in the long run if I wanted to have more current, and in any way should lower the losses in the tranformer and the amount of cooling air needed.

    Edit: Thanks for the translation Bertus
     
  4. kubeek

    Thread Starter Expert

    Sep 20, 2005
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    Here is the comparison of the two transformer designs. The original transformer produces toasty 70W of heat at 130A output current, while the new one only 26W and 53W at 200A. The calculations were made in Mathcad and are enclosed in the zip file.
    I hope there are no blatant errors in the calculations :)
     
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  5. kubeek

    Thread Starter Expert

    Sep 20, 2005
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    Three months later, I have the major parts delivered and I am finalizing the pwm control circuitry and the pcb layouts. Let´s hope I keep my original intention and document the desing process such that it makes sense ;)
    However, i doubt this project will get even with retail prices, but hopefully it will be sturdier.
     
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