Re: Unpotting and such

["Steve Rosenthal" <sdrosen-at-cwia-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

"After not too much run time, the performance suddenly went from 28" to
zero. Diagnosis: One side of the NST was shorted. This, despite my obsessing
over chokes and protection networks! Well, I had read up on the NST
unpotting and repair procedures. I wasn't looking forward to this smelly,
messy job but figured if successful, may result in a better, more robust,
and possibly more powerful transformer if I can remove some shunts.

The top cover of my NST unscrewed, revealing the cracked asphalt surface
covering the transformer guts. I placed the transformer in a disposable
aluminum roasting pan and put this in a covered charcoal barbecue. Several
hours later the asphalt was liquid and I poured off what I could, and dumped
the hot core and coils into paint thinner. After cleaning everything off
with many additional baths and reconnecting the primary and secondary
connections, I repotted the works in the original enclosure and bushings,
this time using melted Vaseline petroleum jelly."

Gary Lau

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, September 02, 2000 6:20 PM
Subject: Unpotting and such


> Original poster: "Sam Beck" <Sam-at-peterbeck-dot-com>
>
> Hey All,
>
> I've got a 15/30 franceformer that I want to unpot.  I've heard
> that the freeze method is bad.  I'd do solvents, but I don't want to spend
> the $$$ to buy them(not yet, anyway).  So can anybody give me tips on
> melting the stuff off?
>
> Also...I'm thinking of keeping the origional case.  Can you use the
> case and fill it with high-voltage oil?  I'd put a liner of bonded acrylic
> in, or maybe just some sort of pre-made container that fit(I've got holes
> already drilled in the base for the Xfmr).
>
> Sam Beck
>
>
>
>