Re: Blown Neon transformers
Subject: Re: Blown Neon transformers
From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
Date: Tue, 2 Apr 1996 17:43:40 -0500
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Subject: Blown Neon transformers
> * Original msg to: Jwatson-at-students.uwf.edu
>Quoting Jim Watson <jwatson-at-students.uwf.edu>:
>> I completed my large transformer today, and two of the four
>> neon transformers went bad after just a few minutes of
>> operation. I was using four 15kV neon transformers in
>> parallel... The spark gap consists of two cylinder gaps in
>> series with a rotary gap.
>If you are running a rotary gap on a coil powered by neon sign
>transformer you are simply begging the neon to fail.
>I don't know how many times I have posted about this:
>Neons or other shunt core transformer don't need rotary spark
>gaps. By placing a rotary gap on a coil powered with these
>transformers you are asking for trouble in the form of a failure.
>These transformers actually deliver better performance with high
>quality static gaps.
>Save the rotary for a pole pig, potential, or plate type power
>supply the requires external current limiting.
>... If all else fails... Throw another megavolt across it!
>___ Blue Wave/QWK v2.12
I don't know how cheap or plentiful neon xfmers are in your area but
here in Ontario, Canada, the neon sign guys like to hang on to good
used transformers for their high resale value in case a customer needs
one. With a new 60MA 15KV neon priced at about $175.00 U.S., before
tax, a customer at a pizza parlor with a sign out will gladly fork over half
that to obtain a good used transformer. I have been able to buy a good
used pole pig like a 10KVA, 16000 volt unit from a utility company
for less than the price of a new neon! With your new .025 cap and rotary break
it looks like a good time to invest in a 5 KVA pole pig. Good luck
with your coil! Sounds like your'e getting there. If it makes you
feel a teensee, weensee bit better, I just blew up two furnace
ignition transformers in the continuing quest to come up with
protection. My new handwound RF chokes (air core 142mH) appear to work
OK by themselves, and I still haven't lost a transformer with them, but when you add
a 250pF bypass cap to the transformer output terminals, KA-BOOO....phttt!
Happy coiling! rwstephens