Re: Self-Resonant SSTC topologies -Morining after.

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Dave,
           I see you mention it here so no need to reply to my last
question on your coil:

On 14 May 2004, at 13:39, Tesla list wrote:

 > Original poster: humanb-at-chaoticuniverse-dot-com
 >
 > Well I messed with my lashup DRSSTC till I blew a IGBT.
 > I added a larger topload, but failed to account for the
 > need to adjust the tank C, DUH! Overall I am very
 > happy. I definitely will be getting some refrigerator
 > tubing, as the #10 wire gets hot. I am very far from
 > anything even remotely efficient, as I was pegging my
 > 15 amp panel meter with only 80-100V into filter. But
 > these sparks are some gnarly nasty suckers! Before
 > killing the IGBT I was getting 24"+ sparks to free air,
 > would suspect that I'd get longer to a ground target
 > (just guessing). So I will rebuild this weekend with a
 > "calculated" tank (not just guessing ;-)), and clean up
 > the wiring (maybe actually solder those caps
 > together!). I will draw up a schematic with component
 > values as soon as possible, but basic setup is as
 > follows:
 >
 > Half-Bridge design from Dan M:
 > http://www.easternvoltageresearch-dot-com/datasheets/sc2045_sheet1.pdf But
 > I am only using 1.5 ohm gate resistance (should I increase this?).
 > Also, I am using two 1.5KE180CA in series across each IGBT (to clamp
 > at 360V). Two HGT1N30N60A4D's that I consider expendable ;-P (will use
 > the  HGT1N40N60A4D's when I get the design down).
 >
 > Secondary with topload and breakout resonates at 280KHz.

I take it that this is the coil using #28 AWG wire? I presume
(dangerous stuff!) that it is a closewound coil? A quick calc shows
the skin depth at that frequency to be a little greater than 3x the
wire diameter. Given that, it would be instructive to compare the
heating if another secondary was used with same wiregauge and same
frequency but spacewound (therefore larger). I'm not expecting you to
do it - just noting that I am presonally interested in the projected
outcome.

Thanks,
Malcolm
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