Re: Is This Neon Trans. Worth Fixing

To: tesla-at-poodle.pupman-dot-com
Subject: Re: Is This Neon Trans. Worth Fixing
From: Tesla List <tesla-at-stic-dot-net>
Date: Mon, 26 May 1997 23:23:28 -0500
Approved: tesla-at-stic-dot-net
Subject:  Re: Is This Neon Trans. Worth Fixing?
  Date:   Mon, 26 May 1997 08:21:51 -0700
  From:  Richard <mackey-at-paclink-dot-com>
    To:  Tesla List <tesla-at-pupman-dot-com>


>> 
>> 
>> I have a 15kv 30ma transformer which pops a 15A circuit breaker
>when the
>> primary is connected to the AC outlet.  There is no connection/load
>on
>> the secondary.  The outlet behaves normally with another
>transformer of
>> the same model.  There is no visible sign of a problem, except that
>> there is a tar leak down one corner, coming from the lid, (as
>though it
>> may have overheated, expanded, and leaked).  I have not yet checked
>it
>> with an ohm meter.
>> 
>> Is there a typical cause for this symptom, and what is the fix
>likely to
>> be?
>> 
>> Thanks for any info.
>> 
>> Tedd
>
>Tedd,
>If the transformer is popping a 15A breaker, then the most likely
>cause of the problem is the primary. The reason I say that is that
>the secondary would have to be drawing 100 ma to have 15A in the
>primary circuit (if the primary was OK). But the current limiting
>shunts on a 30MA unit just won't allow *that* level of secondary
>current. So I doubt if it is caused by a shorted secondary.
>
>Sometimes the primary develops a short either from turn-to-turn, or
>to the case. Do an ohmmeter check between the primary and the case.
>If you read anything lower than 100K ohms, then you have a short to
>the casing. 
>
>If you do not have a short to the case, then you probably have a
>short between adjacent primary turns. As far as the transformer is
>concerned, it "sees" this condition as if it were a fairly normal
>primary coupled to a shorted phantom secondary (without any benefit
>of current limiting, because the shunts are *not* between the primary
>and this phantom secondary).
>
>One other possible cause is a short between the primary leads as they
>come off of the porcelain insulator.
>
>In either case, the "cure" is to remove the transformer from the
>case, or at least to melt the tar out so you can make sure the
>primary leads are not shorting to one another or to the case. If they
>are still shorting, the only cure is to remove the primary and rewind
>it. Bummer.
>
>Hope this helps.
>Fr. Tom McGahee
>

No it is not worth fixing cause all you have to do is go down to a neon
light shop and they will give them to you for free