RE: PT Ballast Question

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

Original poster: "David Trimmell" <humanb-at-chaoticuniverse-dot-com> 

I would use caution in using solid steel in the core of the ballast. I
have tried this and they will get seriously hot! Suggest using laminated
flats from a transformer core, or winding the ballast on the core of
properly rated one. I have noticed a pretty significant voltage drop,
depending on how far you're 'choking' the current. Just my experience.

Regards,

David Trimmell

PS. Sad news losing a fellow high voltage experimenter, my condolences
to the family of Marc Metlicka.

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, October 13, 2004 4:16 PM
To: tesla-at-pupman-dot-com
Subject: Re: PT Ballast Question

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>


I presume you are using some steel rods in the center?  This will
increase
inductanc and limit current even more.

You could unwind 250 ft of wire and rewind this onto another spool.
Then
use both spools in series with steel rods inside each spool.

This should increase the inductance even more and perhaps hit your
target.
If necessary, this procedure could be repeated using 3-4 spools in
series.
You could also rewind the wire onto a carpet tube (free at carpet store)
and
make a steel rod core (1/4 inch rods) that could be moved in and out to
adjust the inductance as required.

Dr. Resonance

  >
  > I recently picked up a nice GE 1.5kva 100:1 pt and
  > have a question or two about limiting the current it
  > pulls from the line.
  >
  > I set up a jacobs ladder using a 500ft spool of 12ga.
  > wire for ballast (as suggested by Terry Blake) and
  > found that it did indeed limit the current to around
  > 26 amps.
  >
  > I'd like to reduce the current further (to around 12
  > amps or so) before I incorporate this transformer into
  > my coil.  Would it be feasible to add another 500ft
  > spool of wire in series with the first?  Any guesses
  > how much additional current limiting this might give
  > me?
  >
  > One other related question... If I were to get a MOT
  > or two to use as ballast, would this be more effective
  > than the wire spool method?  I'm keeping my eyes open
  > for an old arc welder to use as ballast, but in the
  > meantime...
  >
  > All replies appreciated!
  >
  > Thanks,
  > Greg
  >
  >
  >
  >