In a message dated 6/9/2004 3:07:54 PM Eastern Daylight Time,
jemelectric@MWEB.CO.ZA writes:

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




Most of the DC welders I have seen are just that Direct Current, no
frequency involved.  There are two basic types, straight polarity and  reversed
polarity.  They are available as 220VAC input voltages right off  the shelf.  And,
the ones for home use, are usually priced around or  under $300.00 without a
gas conversion kit to use them as a Mig type.  Try  checking the Wholesale Tool
website  _Wholesale Tool Inc - Hand  Tools, Power Tools, Machine Tools, and
Shop Equipment._ (http://www.wttool.com/Merchant2/merchant.mvc)   I am  assuming
you are talking about making a welder to weld metal.

Hope this helps, maybe you can get some information from one of the
manufactureres there.

Randy  Abernathy
4626 Old Stilesboro Road NW
Acworth, GA 30101-4066
Phone /  Fax: 770-974-5295
Cell: 678-772-4113
E-mail: Cnc002@aol.com

I  furnish technical support, repair, and other related services for your
industrial woodworking machinery. My background as Senior Service Engineer for
the SCMI Group for nearly fifteen years with factory training, combines with
my  extensive background in electronics, mechanics, pneumatics, electrical and
CNC  machinery to offer you needed support for your  machinery.

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