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