Roland,

 All the DC welders I have ever seen were basically Motor/Generator type
 units.    The only welders I have seen that use transformers were AC arc
 welders.   They do have output currents of 160 Amps and more typically.
 My dad used to have one that put out in excess of 200 amps.  It was a
 Twentieth Century brand.  The current was adjusted by moving a lever on
 the front panel of the machine.  This in turn moved the core in and out
 of the transformer.   And obviously, it operated on 60 hertz AC.

                                                   Regards,

                                                     Jim



> Hi
>
> Has anyone had any experience with high frequency DC welding circuits.
>
> I've often wanted to experiment with making a DC welder, single phase
> in(220V local), but large ferrite cores are hard to get hold of. Then
> the other day, at the scrapyard (favourite haunt), I came across the
> output section of a small DC welder. The output panel dial showed up to
> 160A, but I was amazed to see that the main HF?? transformer had metal
> laminates. The size was approximately 70mm x 70mm.
>
> I thought iron laminates max-ed out at about 1KHz, which would never
> yield that conversion, unless they're using Silicon steel, but I don't
> know how common that is.
>
> Further searching points to the likelyhood that the transformer is iron
> laminate, switched at about 400Hz.
> Also, the transformer found had only one primary winding, ie not a
> push-pull as I would imagine.
>
> Any ideas?
>
> Regards
> Roland Jollivet
>
>
> JeM Electric cc
> PO Box 1460
> Kloof
> 3640
> Kwazulu Natal
> South Africa
> Tel: +27 31 7024412
> Fax: +27 31 7011674
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> Email: enquiries@caon.co.za
>
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