RE: 15000V/120 ma NSTs, other XFMRs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dave Hartwick by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ddhartwick-at-earthlink-dot-net>

Steve,
All very interesting! These units are made by GE. The large sides are
removable--dont know if that makes a difference. By the time futz around
with  shipping one or both, I may as well have a shot at unpotting.
What is the state of the art in unpotting?? Heat, solvents, dry ice...?
Dave Hartwick



Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<srward16-at-hotmail-dot-com>

About unpotting,

What brand are the transformers??  Here is my list for good and bad
transformers to unpot.

BAD
1, Allanson 15/30-couldnt seperate core, useless because of that
2, Magnetek(jefferson)15/60 hard to insulate after repair(not enough room),
shunts arent removable, actually part of the core!
3, Transco-15/60 difficult to seperate core, and tar is unusually gross

GOOD
1, Any France!!  easy to remove tar after freezing with a screwdriver, core
is simple and coils are wraped in tape so they dont get damaged from pulling
off tar,  All 4 of the transformers i rebuilt from them were a success. And
i have about 6 more on my list to unpot

It IS messy to de-pot them.  Use an ohm meter to check for normal secondary
resistance.  If both test good, then the transformers is most likely ok.
Most transformers i rebuilt had either DEAD or WEAK secondaries, but all
work perfectly when unpotted.  Id love to get my hands on a 15/120,
definitely worth the rebuild effort in my opinion. IF i had the money, and
shipping were free :)  I would be one of those coilers who see those 15/120s
as gold, but i have a supplier for all kinds fo 60ma units for free:).  Good
luck,

Steve Ward.



>
>...But the most interesting items in my collection are 2 - 15000V/120ma
>NSTs. These must be rare, since I rarely read of other coilers using them.
>
>The problem is that one is dead, the other weak. I assume un-potting will
>fix this, but I wonder if it is worthwhile? I stopped using NSTs some time
>ago when I discovered MOTs would work--and then  finally bought a Piglet.
>Still, for a smallish coil, one of those big NSTs would be ideal.
>
>I've never un-potted an NST. I know it can be a mess. Maybe I should simply
>sell these units as is for someone else to do the un-potting, but I wonder
>if coilers would be interested in NSTs of questionable operational status?
>Dave Hartwick