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Re: Post-toasted neon



Subject: 
        Re: Post-toasted neon
  Date: 
        Thu, 20 Mar 1997 12:17:30 -0500 (EST)
  From: 
        Esondrmn-at-aol-dot-com
    To: 
        tesla-at-pupman-dot-com


In a message dated 97-03-19 23:05:01 EST, you write:

<< Not a happy hello,
 
 I toasted my 12kv-at-60ma franceformer. Damn. I was using a variac
 and it must have been the 140VAC. Now when I plug in the transformer
 I get 1 quick big spark and then it starts smoking around the
 HV bushing. 
 
 I have a couple of questions.
 
 1) Does the smoke most probably come from the insulation or
    from the windings or both.
 
 2) If unpotted, is it possible to remove the spools and rewind
    them or does this require a certain machine. I would think 
    the secondary windings might be the 'hair' type wire and 
    easily broken. I would think that the core of the transformer
    is still good.
 
 I found a price for a new Magnatek (formerly Jefferson) $122.68 OUCH!
 
 Bob Schumann
  >>
Bob,

Sorry to hear about you loss.  My pile of neon sign transformers has
about
half toasted and half good.  It is not unusual to destroy a few of
these.
 Are you using series inductors and resistors in the high voltage leads,
and
a safety gap?

Don't run the transformer any more.  It is possible that a carbon short
path
has developed in the tar.  This is the usual failure mode.  Possibly
unpotting it and careful work can save it.  You are right, the wire is
very
small diameter and fragile.  Rewinding new secondaries is not very
realistic
unless you have the proper automatic winding equipment.

Ed Sonderman