Re: Arc Welders as Rheostats?? Variac Mod Question

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

Original poster: "Jack King by way of Terry Fritz <twftesla-at-qwest-dot-net>" <speakernut-at-yahoo-dot-com>

Anyone out there have data on how "wide" the air gap
needs to be? My gut says something like .75-1" should
be sufficient to interrupt the flux travel...any
thoughts? I'm toying with "modifying" a 7.8 kva unit
for use as a series reactive ballast, and would like
additional insight before i dig out the band saw.
Also, does one need to replace the removed section
with epoxy or something along those lines to maintain
structural integrity? Lastly, might anyone know off
hand if cores on these older, larger dogs are silicon
steel strip or scintered iron encapsulated in epoxy?

Cheers,

Jack King


--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Barton B. Anderson by way of Terry
> Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> 
> Hi Chris,
> 
> Tesla list wrote:
> 
> > Original poster: "torlin by way of Terry Fritz
> <twftesla-at-qwest-dot-net>"
> <torlin-at-ghostmail-dot-net>
> >
> > Here's a silly question, why would one want to cut
> up a
> > variac?  I seem to have missed this tangent of my
> original
> > question, as to how to use an AW as a variac.
> >
> > Chris
> 
> Not a silly question. Cores have been cut in the
> past to prevent the core
> from saturation when
> used as a ballast (there are limits even to this).
> It's not recommended
> because it ruins a
> perfectly good variac for it's normal use. If so
> much current is being run
> through a variac
> that the core is saturating (loud buzzing hum), then
> get a larger variac.
> If a variac just
> can't be obtained, then the core can be slit to
> prevent saturation (but the
> variac is then
> limited to it's use). I believe several posted on
> how to connect the welder
> as a ballast. The
> archives are full of info on this as well. I
> personally use a variac and
> not a welder, so I'll
> let those coilers talk about that.
> 
> Take care,
> Bart
> 
>