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Re. wether or not to mess with repotting NSTs
>Original Poster: "chris morgan" <crmorgan-at-hotmail-dot-com>
>
>Today, me and ramsey got 20 NSTs from a local distributor.
Excellent score!!! What's a distributor, as compared with a sign shop?
>So far I've
>tested 11 and 6 have worked well enough to create a spark (1/4" for 9Kv,
>3/8 for 12 or 15 Kv) When I was talking to the guy there, he said that
>many NSTs were returned just at the point were they could no longer
>start a neon sign. Should I bother to mess with these? They'll
>probally get worse, but I don't know. Also, all of these have had the
>labels removed, so I don't know what there rated at. What are som good
>techniques for mesureing the out put?
Apply line AC voltage across the secondary terminals and measure the
voltage on the pri and sec terminals. The measured voltage should be
something less than a volt across the primary. If Vsec is 115V and Vpri
is .882V then the output voltage if it were hooked up normally would be
(115)squared/.882 = 14,994V
The output current may measured by essentially shorting the secondary
terminals (this is okay to do with a current-limited transformer) with an
AC current meter and applying nominal 115VAC to the primary. Just read
the current meter. Be careful not to touch anything when energized.
>They came in three sizes. The
>smallest were the same size as all the 9Kv 30 ma units I've seen, the
>medium size were around the same size as all the 15 Kv 30ma units I've
>seen, and the largest ones came in even larger boxes. Would a 15 Kv
>60ma NST have a larger case than a 30ma NST?
Yes. My 15/60 measures 9.5" x 5.5" x 6.0" (MUCH heavier),
while my 15/30 measures 11.0" x 3.75" x 4.75"
Definately save and repair if necessary the 60 mA output units, they're
hard to come by. Unpotting and repotting is an unpleasant procedure, but
the NST will be a better, more durable unit when done.
> i also have 4 small black boxes. He said they produced HV without a
>transformer, so I'm assuming there voltage multipliers(with HV diods I
>want to get my mits on) Would the heat neccesary melt the tar damage
>the diodes. Or should I freeze it or dissolve it with gassoline.
>
>Chris, via the inter-thingy
Gary Lau
Waltham, MA USA