Re: SSTC achieves 36" Streamers! - Thanks to Justin

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

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>

 > Continous with no problems huh?! Awesome!!!
 >
 > Glad to hear you've got it working good.
 >
 > You said that performance drops off with less than 4 turns?
 >
 > I have noticed that if too much current is pushed through the
 > MOSFETs, the arcs start off long and then shrink to almost 50% of the
 > original length. This happens REPEATEDLY with an SSTC Aron just made.
 > It's a half bridge running at 120V...using IRFP460's and a 4-turn
 > primary. The 20 amp parts just aren't cutting it, but the 50A FET's
 > we just bought will. It will be fun to compare the 20A and 50A
 > parts...it will make an interesting post here.
 > Anyhow, Dan, do you think you could be running too much current for
 > your parts, or perhaps it is some other issue (such as magnetizing
 > current of the primary vs. uncoupled inductance)? Anyhow, if a SSTC
 > bottoms out at 3 foot arcs with 240V input....that's significant.

Yeah, it definitely seems with this coil that anything less than 4 turns
really affects performance.

The IXFN24N100s are rated for about 23A continuous each, but can be pushed
much higher with adequate heatsinking and cooling.
The FETs themselves can dissipate up to 500W each with proper cooling!

Another weird thing that happened is my performance this evening when I
tried it was limited to about 28 inch arcs.  Nothing changed - input voltage
is the same as it was measured
yesterday.  Only thing different is the weather, but I hardly thing that
would matter.  Still investigating why I cannot repeat this performance this
evening . . .

Anyways, I'm in the process of taking some pictures and video, as well as
capturing my voltage and current waveforms and posting them on my site.

Thanks again.

The Captain