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Re: I wonder ...
Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Pyrotrons-at-aol-dot-com>
Hi Garry, All.
Not to go against your previous post in any way, I would just like to
mention something as far as Magnetek's "Jefferson" NST goes.
A couple of years back, Aron and I had an old 4.5" running at 900VA, the
components of which went to Heck and back numerous times. We used:
* No safety gaps
* No form of filtering or kickback suppresion (such as Terry's filter)
* A perfectly resonant MMC cap value (measured .010663uF), made evident by
the LOUD 60Hz hum, heard above the rest of the coil noise and gap firing at
15VAC input from variac (serious resonance)
* Spark gap out to .4" on every run, sometimes to 1/2"
I think most people on this list agree that this is asking for problems.
The coil was mostly run continuously from 15 - 30 seconds each time
(hundreds of times) sometimes going to 2 minutes, and a few runs being 5
minutes long. Total runtime seen by all coil components is approximately 3
hours or more.
The Jefferson 15kV 60mA NST worked excellent throughout those 3 hours, and
right now It's running a jacob's ladder downstairs in the garage.
I haven't ever been inside a Jefferson, and what you've mentioned about the
difficulties in unpotting is correct I'm sure. People don't need to buy a
Jeff for unpotting. What I do know, is I have never *needed* to get into it
(other than wanting to modify and get 250mA out....this is possible and
won't fry a 60mA trannie...Aron has proven it over and over...). My
transformer (given to me by Aron years ago) has far exceeded my expectations.
A special case? Possibly, possibly not I think. You mentioned some sort of
silicone that raises the melting temp of the tar...this is much unlike
other NSTs I've seen inside (but I haven't been inside that many). So
calling all Jeffersons, please let us know long your xfmr lasted (or is
lasting) in what kind of coil service.