Re: Non ballasting a pig?

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Ken,

Your transformer (although hefty) isn't a pole mount beast. I wonder if
there is sometype of internal
limiting? Maybe not. The time it takes to magnetize the core is not
instantaneous. During that initial
di/dt, the transformer will attempt draw as much as it is allowed to. For
whatever reason, be it a higher
R of L1 or some other  cause, your transformer isn't cabable of drawing
enough current to pop the mains
(or worse). My beast will! I made mistakes early on in the ballasting arena
and blew 30A easily. L1 dcr
on my pig is a dead short (0.2 - 0.3 ohms).

Although there may be transformers which for some unkown reason do not
appear to draw currents in excess
of mains capability, in general, large transformers without internally
ballasting must use external
ballasts, for the safety of the component, the house, and the user.

Take care,
Bart

Tesla list wrote:

> Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<tesla-at-lists.symmetric-dot-net>
>
> Why would it appear as a short unless you short the output windings?
>
> The coil I'm working on will be DC powered so I don't have to play the
> impedance matching and current limiting game with my polemount transformer.
>
> KEN
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Monday, October 14, 2002 9:32 PM
> Subject: Re: Non ballasting a pig?
>
> > Original poster: "Barton B. Anderson by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> >
> > Hi Gregg,
> >
> > You "must" ballast the pig regardless. Connecting the pig without a
> ballast
> > will appear
> > as a short circuit. These transformers will pull many times their rated
> > amps in short
> > circuit conditions. Take the recipricol of your percent impedance value
> and
> > mulitply by
> > your rated amps. This will give you some idea of what the pig would try to
> > draw. Your
> > breaker would pop immediately.
> >
> > My pig is 1.9% imp 10kva/14.4kv.   So 1/1.9 = 52.6 x 41.67A = 2192A =
> gotta
> > use a
> > ballast to limit current.
> >
> > Take care,
> > Bart
> >
> > Tesla list wrote:
> >
> > > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <network-at-neXband-dot-com>
> > >
> > > Hello list,
> > >    I've been following some posts where ppl are talking about what it
> > > takes to ballast a pig and was wondering this...
> > >
> > > I recently installed a new breaker box(200amp) in my house in which I
> > > reserved a 100amp 240v breaker for my shop.  Is it possible that this
> > > would be enough to power my 7.5kva pig without ballasts?  If I still
> need
> > > to, would one 3000w heater element be enough even though it's lossy?
> I'm
> > > not fortunate enough to have a stick welder, just a wire welder and the
> > > water heater element is handy;)
> > >
> > > Thanks,
> > > Gregg Adams
> >
> >
> >
> >