Re: Neon Sign Transformer - Basic Questions

To: tesla-at-pupman-dot-com
Subject: Re: Neon Sign Transformer - Basic Questions
From: "Travis Tabbal" <bigboss-at-xmission-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Wed, 24 May 2000 11:36:12 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Tesla List wrote:

> Original Poster: Irrelative-at-aol-dot-com
>
>     I just got myself a neon sign transformer (9000v, 30ma) and want to make
> sure I take care of it.  There seem to be sites about everything on tesla
> coils so I was wondering if there were any about the anatomy of transformers
> and how to rig up some protection for them.  Any information would be
> helpful, such as how to de-pot and restore a fried transformer.  Also, on a
> side note, I highly respect the talent of this group and was wondering what
> you would recommend for a spark gap considering my input of 9kv and 30ma -
> static, static vacuum, rotary?  Anyway - thanks in advance.

Welcome to the list. For the protection I use an RC filter that Terry Fritz
designed. I don't have the link here at work, but I'm sure someone will post it
or Terry will add it into this message before sending it to the list..
*hint* ;)

http://users.better-dot-org/tfritz/NSTFilt.jpg

Also, a safety gap goes a long way toward helping keep the NST alive. I use the
3 point style, center to ground, and both sides to the NST HV terminals. Just
adjust it equally on both sides to where it just barely can't fire when the NST
is the only thing connected. Be sure to unplug the NST before adjusting it. ;)
Trust me, they HURT, you don't want to get shocked by one.

De-pot? Never had to. ;) But you have a lot of options here. You can heat it up
and melt the tar, or freeze it and chip it off. Or soak it in solevent for a
while. Probably a few I missed too. If you have one side short on you just try
melting it and letting it cool again. That has fixed a large number of NSTs in
the past for people. You can try to de-pot and remove shunts to get more
current, but you could blow the NST that way. Personally, they're cheap so I
don't bother. I just get more and run them in parallel. Plus I have a pig, so I
may just stop using NSTs altogether when I get off my butt and finnish my power
controler. ;)

For the power level you are running at with a 9KV 30mA NST you would be fine
with a static gap. I would recomend the RQ/TCBOR style as they are easy and
cheap to build. There has also been discussion of flat ones like the Scott gap.
Just do a search on the net or the list archives at www.pupman-dot-com and you will
find a ton of info on them. The basic idea is that the electrodes are made from
copper pipe fittings you can get at the local hardware store. Set them side by
side and you have a gap. I use about 8 .03" gaps in my 15KV coil right now.
There is a large text file by Richard Quick that details the construction, and
probably no small number of websites.

Travis