RE: some new ideas for the SSTC guys

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

Original poster: "McCauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com> 


Very interesting. Thanks for posting the idea.
I am in the process of taking a hiatus in tesla coiling for
at least six months now so I won't really have time to test your idea.
But i'm sure
maybe Steve or Jimmy would try it.

Dan



 >Problem --- Exploding IGBTs when they are hit with a sec - pri
 >spark (Terry
 >Blake's coil terrible demise at our Teslathon).
 >
 >A few years ago I did some experiments with a flat spiral coil
 >(18 dia.
 >sec.).  In the classic configuration with a .05 uF cap, RSG,
 >and 4.5 turn
 >primary the sec sprayed out 8 ft long sparks.
 >
 >At the urging of a plasma physics guru from UW-Madison (Paul
 >Nonn for those
 >of you who might remember meeting him at Ed's recent
 >Teslathon), I removed
 >the sec coil and placed it on a stand 10 feet away.  I used a
 >7 inch corona
 >ball on the bottom to prevent any corona and used a single tap which I
 >attached to the "normal" primary coil.  With some re-tuning it
 >was again
 >spraying out 8 ft sparks.
 >
 >What I'm getting at here, is, the SSTC experimenters, Dan M.,
 >Steve W.,
 >etc, might try using a larger dia sec coil and then use a
 >15-20 turn test
 >primary coil while feeding the sec coil a few feet away.  If
 >this works,
 >then the greatest danger to SSTCing, ie, blowing the IGBTs
 >should become a
 >problem of the past.
 >
 >It will take some experimenting --- perhaps the best tap is
 >"inside" the
 >normal classic tap location or perhaps it will be "outside",
 >but either
 >way, getting the sec away from the primary to act as a series
 >fed setup
 >should eliminate the IGBT explosion problem.  If it does work
 >the primary
 >can be either a flat spiral or normal solenoid coil ---
 >perhaps enclosed in
 >clear acrylic with a large "feeder" wire over to the sec coil.
 >
 >If someone DRSSTC tinkering wants to experiment with this idea
 >on their
 >present or planned near future coil, please advise and I will
 >send you a
 >nice 10 ft long chunk of #6 AWG for experiments --- with 125 kV BIL
 >insulation --- it's 1 inch thick and offers great HV feedwire
 >performance.  We use this "big Red" on all our HV power
 >supplies to feed
 >the 14.4 kV HV over to the base of the oscillator.
 >
 >Might work, might not, but worth trying.
 >
 >Dr. Resonance
 >
 >
 >
 >