Big SISG Coil First Light - New Charging Circuit Works Too!!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I finally got the larger SISG coil's electronics going today.  It 
works good!!! :-))

This coil uses a new SiSG charging circuit shown here (probably work 
for standard gap coils fine too):

http://drsstc.com/~sisg/files/BigSISGCoil/BigSISG-Schematic.gif

The charging circuit gives the coil a fairly surprising BPS 
range.  It starts at about 70 volts at roughly 60BPS and goes "up" 
from there.  Its nature is like that of an async system.  It seems to 
work pretty much as predicted.  I did not spend much time on models 
for it yet until I could test to see if it worked at all.

There are pictures here:

http://drsstc.com/~sisg/files/BigSISGCoil/P8070190.JPG

http://drsstc.com/~sisg/files/BigSISGCoil/P8070191.JPG

http://drsstc.com/~sisg/files/BigSISGCoil/P8070193.JPG

http://drsstc.com/~sisg/files/BigSISGCoil/P8070195.JPG

There is a VCD format movie here:

http://drsstc.com/~sisg/files/BigSISGCoil/BigSISG.mpg

If you can't get it to play there is a rougher but more basic MPG here:

http://drsstc.com/~sisg/files/BigSISGCoil/BigSISG-alt.mpg

If it is real busy, try back a bit latter.

The capacitors are MMC in a length of plastic gutter pipe.  I could 
have put them all into one the same size.  I may get more caps and do 
that just to save room in the final coil.  I filled them with 
polyurethane foam which works well.  I will hard epoxy the ends someday...

The coil itself is just the old DRSSTC step up for now too.

The SISG is Mark Dunn's board which works fine.  It can easily hit 24 
inches.  I have into measured much yet but the new charging circuit 
should have a very good power factor and all.  The resistors burn off 
heat but it will have a fan ;-))  That is a small cost for the 
simplicity and I don't think it can be blown up.  The SISG IGBTs seem 
to run cold.  I will have to test it to see if I might want to go to 
225W resistors just to keeps things cooler.

The bang power is 1.54 joules at say 185 watts at 120BPS.  It seems 
like one could very easily scale it up but I have not gotten more 
IGBTs yet to fill more boards.  The 237.5nF primary cap seems to be a 
nice balance of primary peak current, energy, Fo, and power.  But 
there or probably things that could be optimized since the resistor 
values were pretty much a guess.

But the main thing is that the charging circuit does actually work very well!!!

Cheers,

	Terry