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SISG success continues... (fwd)



---------- Forwarded message ----------
Date: Wed, 20 Jun 2007 15:33:51 -0700 (PDT)
From: Brett Miller <brmtesla2@xxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: SISG success continues...

All,

Just wanted to report that my SISG research is going
well.  I have perf'd up 3 900v segments, and have been
tweaking the 5k pots:

http://www.hot-streamer.com/brett/temp/3_perf_segments.jpg

...as of today I've managed a pretty decent spark
length at only 45v or so on the variac with these 3
modules:

http://www.hot-streamer.com/brett/temp/SISG_6inch_arc.jpg

My test setup doesn't yet employ the fancier resonant
tripler of Piranha fame, but rather a full wave
rectifier, high side ballast, and single tank cap.

http://www.hot-streamer.com/brett/temp/sisg_test_setup.jpg

Tonight's project (if I have time) will be to replace
some of those old NST wire and 10A alligator clip
jumpers with AWG 12 wiring and spade terminals.  In a
high rms current tank circuit like this the little
resistances add up.  Earlier I found that one of the
clips was loose.  After I secured it, I gained 2
inches of spark length.  It's not a good idea to cut
corners in the wiring here.  

I started off with two segments and only abou 1.75"
sparks.  Now I've added a segment, and rebuilt the
initial two, also utilizing the 5k pots and a smaller
gate resistor.  Spark length has more than tripled.  I
can't wait to get the board you are sending Mark!

Oh, and the 900v segments featured in the photos are
using the Fairchild FGL40N120AND TO-264 IGBTs.  I have
also made two successful segments using Fairchild
G27N120BN and MUR860 for internal anti-parallel diode
replacement.  So you could prett much (as Terry has
already stated) use any IGBT that could take the
current and that you can design a gate trigger for.

http://www.hot-streamer.com/brett/temp

...sorry about the crappy waveforms...I'll have some
better one's with a calibrated scale (and in focus)
soon.

Cheers,

-Brett




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