Re: Pool Pig...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: G Hunter <dogbrain_39560@xxxxxxxxx>

Your coil project is certainly attainable Chip.  What
about ballasting though?  Have you considered that?
You'll need something to restrain your pole pig, or it
will instantly overload your circuit breaker.  I use a
240v AC "buzz box" type arc welder in series with my
pig to limit it to no more than 48 primary amps.  9
runs out of 10, I left the welder leads open-circuited
and ran at only 7-8 primary amps.  This was not only
much easier on my coil setup, but also much easier on
my nerves!  Brief, high power runs were fine for
visitors, but 1700VA was much more useful for
structured play.

Before you go blowing $100 a pop on used Maxwells, try
running the numbers on 150nF/2KV CD942C polypropylene
caps in an MMC grid.  These may give you more nF per
buck than Maxwells.  5 parallel strings of 10 caps
would yield a 75nF/20KV MMC.  That should give your
pole transformer a reasonable cap size to work with.
Once you get the thing tuned up and working, you could
always parallel a second unit with the first one for
150nF total.

Cheers,

Greg

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: <chipford@xxxxxxxxxxxx>
>
> Thanks Greg. This is comforting. I have a buddy that
> works in the
> electric utility business. They are the folks that
> sub-contract
> replacing the end of shelf life poles and stuff like
> that. He tells
> me he can get me a 10 or 15kva pole pig pretty easy.
>   He said that
> about all of them are the 7200 volt variety.
>
>   With all of this said, can I just build a say 8
> 1/2" dia. X 48"
> secondary with about 1200-1400 turn of 20-24awg wire
> on it and then
> lay down 10-15 turns of copper tube say 24" diameter
> 1/2" apart, hook
> a couple of .03uf X 30KV maxwell caps in, hook it to
> my pole pig, do
> some tweaking and create lightning? ;^P
>
> See attached photo...
> http://hot-streamer.com/temp/variac-0a.jpg
>
>
> ---- Tesla list <tesla@xxxxxxxxxx> wrote:
>  > Original poster: G Hunter
> <dogbrain_39560@xxxxxxxxx>
>  >
>  > Hi Chip,
>  >
>  > The transformer / cap matching formulas often
> break
>  > down when pole pigs are involved for precisely
> the
>  > reasons you've just illuminated.  An optimal cap
> for
>  > 7200vac at 2 amps is just too big.  It's not a
> big
>  > deal.  Smaller-than-resonant caps are the norm at
> such
>  > power levels.  Start off with about 50nF and
>  > incrementally add capacitance until you get
> decent
>  > sparks.  Maxwell Labs 30nF 30KV plastic caps go
> for
>  > about $100 apiece on e-bay these days.  Try one
> or two
>  > of those to start with.
>  >
>  > Cheers,
>  >
>  > Greg
>  >
>  >
>  > --- Tesla list <tesla@xxxxxxxxxx> wrote:
>  >
>  >  > Original poster: "Chip Ford"
> <chipford@xxxxxxxxxxxx>
>  >  >
>  >  > Ok...there are many kinds of transformers out
> there.
>  >  > Seems that the
>  >  > really BIG coils use a pole pig. Such as "The
> green
>  >  > monster". His is
>  >  > a 15kva @ 14400 volts. Using the math KVA =
> ((VOLTS
>  >  > X AMPS) / 1000),
>  >  > I came up with an amperage of @ 1.042 Amps
> (15,000
>  >  > watts). Since .001
>  >  > Amps is equal to 1ma, he has 1042ma. According
> to my
>  >  > calculations,
>  >  > the resonant cap is @ .1919 uf. I think he
> said his
>  >  > cap was
>  >  > .1uf...close but not real close..Now, I think
> alot
>  >  > of the line
>  >  > transformers have a selector switch on them. I
> think
>  >  > they are like
>  >  > 7200, 6400, 5600 volts for the ones around
> here. So,
>  >  > if I have 15 kva
>  >  > transformer @ 7200 volts, it will have an
> amperage
>  >  > of @ 2 amps
>  >  > (2000ma)(15,000 Watts). At this rate, my cap
> is
>  >  > gonna be around .75
>  >  > uf. This is really high and from a few
> calculations
>  >  > that I have made,
>  >  > A secondary coil 12" 81/2" dia. 48" tall will
> need
>  >  > over 10000 turns
>  >  > of #39 awg. wire on it. This pretty much makes
> this
>  >  > transformer
>  >  > unusable. Besides that, where is a hobbest
> ever
>  >  > gonna find a cap? Am
>  >  > I missing something here? Are my calculations
>  >  > incorrect? Am I looking
>  >  > at the transformer incorrectly? Please
>  >  > comment...Chip Ford
>  >  >
>  >  >
>  >  >
>  >
>  >
>
>
>
>