Re: Correction: It's Me Again

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

Original poster: "sundog by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sundog-at-timeship-dot-net>

Hi Ryan, All,

  If you're running that pig at 800-someodd mA, then you're
probably powerarcing (spotwelding more like) your gap.  Choke the
pig down to 200ma or so (by running it on a 120v line to the middle
and 1 outer tap for the full 14kv on the HV side)  You should be
pulling around  18-20A on the 120v line.  Even rotaries will
powerarc with huge charging currents on 'em.  Ballast that puppy
down a bit more :)  Run it on 120v if you have to to get the
current down to a some-what more sane level.

 On the capacitance, yep, you're looking at a biiiiig cap to run
reso on a pig.  Most guys get the biggest cap they can afford and
run a higher breakrate than 120bps (300-800bps more commonly).

  Keep in mind that a pig system can easily pulverize most caps!
With only 30nf available, I'd definatey keep the pig choked down in
current to avoid literally baking your caps!
  Also, if those are the same caps I'm thinking about, (1200v.22uf
Panasonics), they use a mylar dielectric and will heat *very*
quickly in TC service.  I've gotten them to work find on a small
(9/30 NST) running DC and a single static gap, but they heated
pretty good in the same setup running a 9/60. Just a heads up (I
bought them from Bill Noble, I believe)

My advice is to choke it down by both mots in series (the mots
should have the secondary shorted to the core), and run it off
120v.  Check the MMC frequently for heating too, because if those
are the caps I think they are, I'm almost positive they're mylar
(polyester).

          Hope it helps!
                                            Shad



-----Original Message-----
From: Tesla list <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Sunday, January 07, 2001 1:17 PM
Subject: Correction: It's Me Again


>Original poster: "Ryan Ries by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <spud-at-wf-dot-net>
>
> I apologize for my last post, I was really not thinking right.
(As I
>mentioned, it had been a couple months since we had looked at the
coil).
>Anyway, right when I woke up this morning, I realized that huge
capacitance
>I was talking about was a matched capacitance for the transformer,
and not
>really what we were shooting for at all.  So now we have to find
what else
>could be the problem.  The ballasting is two microwave oven
transformers in
>series.  This seems to be the general consensus on the list about
what is
>the best ballast (for the money).  The spark gap is a single
static
>air-blast spark gap with brass electrodes.  This is a bad gap for
a pole
>pig I know, but it should still be able to get SOME spark out of
the coil.
>The primary and secondary coils are beautiful, so I'm a bit vexed
here as
>to what could be our problem.  I realize pole pigs are totally
different
>beasts than NST's, so I'm trying to be patient. :)
>
> Thanks again,
>    Ryan Ries
>
>
>
>