Re: fixing a transformer

To: tesla-at-pupman-dot-com
Subject: Re: fixing a transformer
From: FutureT-at-aol-dot-com (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Tue, 06 Apr 1999 01:11:53 -0600
Approved: twf-at-verinet-dot-com

In a message dated 99-04-05 04:39:02 EDT, you write:

<< Original Poster: "Andy Cleary" <gemware2-at-dreamscape-dot-com> 
 
 >        I recently was given a very nice neon sign transformer (15kv 30ma) 
for
> my
> first coil, the only problem being that it is partially broken.  I do not
> want to buy a new transformer, because they are quite expensive and I am
> sure that I'd break it.  I have read of a way to fix this kind of
> transformer by placing it in the oven to reheat the potting material which
> would remove the carbon traces.  How good is this technique?  If it is good,
> what should the setting of the oven (conventional I assume) be on, how long
> would it take, etc.?  Thank you very much,
 
> -Andy
  >>

Andy,

The cooking technique works occasionally, it depends on the problem
in the transformer.  If wires are shorted, nothing will help.  Some types
of tar don't melt well either, such as the Jefferson/Magnetek types,
which often have a filler material in the tar.

There is a very simple solution though;  go to a neon shop, and ask
for a NST that's burned out on one side, then ground the cases of
both NST's together, and you'll get 7.5kV from each, for 15kV total.
Power both NST's from the 120 line in parallel, or put the primaries
in series and power using 240 volts.  You may have to reverse the
connections to one NST input to phase them correctly to get an
output voltage.  I'm assuming your NST is good on one side.

Better yet, tell them you're a student and poor, etc, and ask them
for a good free NST, or pay them $5.  Go to a few shops and ask,
don't call them on the phone.  NST's are out there for the picking
(cheap), you don't have to spend a fortune ($150) to buy them new.

I've often seen NST's for sale for $20 on this list, does that seem 
expensive to you? 

If you're building a first coil, consider oil burner transformers (OBITS)
too, you can get them from oil burner repair shops for free, etc.

Happy coiling,
John Freau