Re: old welder questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Eric Davidson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <edavidson-at-icva.gov>

Marc,

Though I dont have any direct knowlege of your welder,  I may be able to
shed a little light on its possible operation.  Almost all motor driven
welders are used to generate direct current for the actual welding.  DC
welding has several advantages, a couple being a much more stable arc and
the ability to change the polarity of the stick with regard to the work.
Depending on how old the welder is, good, cheap, reliable, high current
silicon rectifiers may not have been available, so a generator was used.
The "continuous tap resistor" you see may be used to adjust the field
current of the generator.  The "diamond shaped split core inductor" may be
used for arc stabilization, as a sat-react would not regulate direct
current.  Careful and thorough inspection will shed light on the
construction and circuitry. A schematic from Lincoln would be soooo sweet.
To my limited knowledge, saturable reactors are not use to regulate current
in arc welders.  In AC welders, the current is regulated by changing the
reactance of the transformer itself, by changing the positions of the core
and/or coils. Take another look at the cricuitry and let me know what you
find out. I hope this helps.

Eric
edavidson-at-icva.gov


> Original poster: "Metlicka Marc by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
>
> hello all,
> I am hoping some coilers may be able help me with an old welder? I have
> a lincoln model (sae 200-1) 3 phase motor driven dc welder that uses a
> massive continuous tap resistor that looks like a crane resistor unit?
> It also has a "BIG" diamond shaped split core inductor that looks like
> it may be a saturable reactor????
> The one side of the reactor uses a flat inductor wrapped edgewise around
> the core, the other side has 12g windings. The problem is that the
> reactor side is fed from the generator through a 50 watt rheostat and is
> labeled "voltage" , the "continuos current" side runs through the
> massive resistor unit.
> So, What the heck have i got here? At first glance i thought "now here
> is a dandy ballasting setup" resistive and saturable reactor current
> control all in one unit that just MAY be built into the ultimate 0-200
> amp power control rack, But now i'm confused.
> How is the saturable reactor used for voltage, or is this a funky auto
> transformer?
> Any help from those that have seen or understand this setup will be a
> blessing.
> Thanks,
> Marc M.
>
>
>