Plasma Jet Ignition/TIG setup

[Chad Clendening]

I took at the guts of a 175 amp Lincoln TIG.  It appears to use a series
transformer to put the high frequency on top of the AC / DC source for
welding.  It has a circuit board about a foot by a foot with a portion of the
circuitry siliconed over to control everything.

This unit had several SCR's or triac's, don't know exactly what they are used
for.

Chad

Clarence L.Snyder wrote:

> Tony Bryant wrote:
> >
> > > bob at bobthecomputerguy.com (Robert Harris) wrote:
> > >
> > > >Re-reading my Heywood and have become re-in-love with the concept of
> > > >plasma jet ignition.   Essentially, a normal CD ignition fires the
> > > >plug in a cavity connected to the main chamber by an orifice.  Once
> > > >the arc is established, a second low voltage high current capacitive
> > > >discharge is routed into the arc.
> > >
> > > Hey - I like the sound of THAT.  Did someone get this working?
> > >
> > > This reminds me of the arc stabilizers you find on TIG welders - a high
> > > frequencyt current starts the pilot plasma/arc which then allows the
> > > main welding current to flow on through...
> > >
> >
> > I've also been toying with this idea for a while, but I can't see how
> > you can connect a HV, LC and a LV, HC source together. The
> > seemingly inevitble problem is the LVHC source must be low
> > impedence, and therefore absorbs the HV in preference the spark
> > gap? How are these TIG welders arranged?
>
> Something called a DIODE, I think. Actually on the TIGs it may be an
> SCR.