Re: Non ballasting a pig?

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

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

> 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

It sure is. http://energybeam-dot-com/tesla-coil/10-24-2001/transformer.jpg

> 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

It's possible the wiring where I lived was a bit thin and added the
resistance needed to keep things from catching on fire and exploding. I even
plugged it in over and over again with a 0.04uF cap across the HV terminals
to insure I had load (reactive but current is current) of which was about 13
amps

> 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.

I have to disagree on principal here. If you cannot power on your
transformer with no load, you clearly either have a transformer that is way
too big, or a power mains that is too small. Power transformers in buildings
are not ballasted, you don't ballast your television set, and you don't
ballast your power tools. Microwave ovens have mean transformers and they
are not impedance limited. They do require a 15 amp circuit breaker though
ad run at less than 2kVA. So to keep your distribution transformer happy it
might make sense to have at least 5 times the power available or 2.5 times
the 15 amps if you power it off 240 volts. I did take a look at this
reactive load test:

http://energybeam-dot-com/tesla-coil/01-08-2002/Krodak-pole-meters.jpg

Note the current meter bezel is too high by a factor of 10 and the volt
meter is measuting only voltage across half the 240 input. The line voltage
looks a bit low for what we have here in Chicago, so maybe it was just trash
wiring keeping the current down. Transformer is currently idle and has no
place to be plugged in now at all.

I should haul it out to a factory with a large power feed and try to measure
the surge current during the first half cycle of AC input.

KEN


> > 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
> > >
> > >
> > >
> > >
>
>
>
>