Re: Pig inrush limiting

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Thomas Coyle" <zxcasd@xxxxxxxxx>

Thanks, Jim - all great questions. I'll get all the answers tomorrow 
when I finish unearthing everything.

Oh - and I am using the 1/2" copper for the ladder - this also came 
in the package when I bought this whole suite of toys from a retiring 
coiler, so I know it was working for him at one point! The only shame 
is that I can't get the 9-foot-tall VDG that I also bought from him 
hooked up - it's too tall for my garage when fully assembled and the 
discharge terminal alone weighs 200 pounds (he homemade it from 
fiberglass and aluminum tape) so I can't just put it on and take it 
off easily to run it outside - it's been amazingly dry lately, so I'm 
sure I could have had some fun with that. Oh well.

On 10/19/06, Tesla list <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: "Jim Mora" <<mailto:jmora@xxxxxxxxxxx>jmora@xxxxxxxxxxx>

Thomas,

Ramping up the voltage is a good thing as you could bring it to the max
before the breaker trips. Otherwise you're inviting inrush. I ran my Pig
(much smaller) at 50amps. That's when the flames gets knurly to use CA
speak. Be sure to use posts that won't melt, I had 3/8 steel. I think others
use hard type 1/2" copper tubing.

Someone else may want to discuss ballasting a 25KVA... out of my present
league. Too bad someone just bought my 20KVA saturable reactor. You say "one
of" your big variacs. If its heavy enough, run the other one in series on
the down hill side of you voltage variac so you can control current and
voltage. Just be sure to Mains ground the variac cases. What are the variacs
rated at? Also what Size wire is in you dryer jack?

Hmm I was asking this not long ago...

Big Flames,
Jim Mora

-----Original Message-----
From: Tesla list [mailto: tesla@xxxxxxxxxx]
Sent: Thursday, October 19, 2006 6:18 PM
To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx
Subject: Pig inrush limiting

Original poster: "Thomas Coyle" <<mailto:zxcasd@xxxxxxxxx> zxcasd@xxxxxxxxx>

Well, I got some of my stuff out of storage including my 25kVA pig, a
resistive ballast (pair of large heating elements that measure out to
about 7 ohms), and various other odds and ends. I saw this pig in
operation before I bought it a year or so ago, and then immediately
stuck it into storage. Now I want to fire it up with just a jacob's
ladder to see if it still works (and because I've never done a JL on
anything except an NST), but I'm concerned about the inrush draw on
such a monster.

If my math is right, that resistive limiter should keep the pig to
under 20 amps, and I'm planning to plug it into my 30 amp dryer
outlet in the garage. So, presumably no problem. But - can I get away
with just plugging it in with the circuit breaker off, and then
turning on the breaker? Or should I stick one of my big variacs in
between and ramp up the voltage slowly?

In short, what can I do to get pretty sparks without blowing
breakers, melting my pig, or killing myself?

I'm getting the rest of my Big Coil parts out of storage tomorrow, so
if this thing works I'm going to try to throw it back together this weekend.

Thanks!

Tom