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

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Again,

I got a MicroSim model working for it!!! It is hard since so much is floating and MicroSim hates fast moving floating currents and voltages and presents convergence errors. But this one is usable:



You will have to change the model instance text so that the two diodes will hold off say 100kV... ;-)

But with 132V peak in (93Vrms) I get this for the firing current:


I don't "explain" the graphs, I just "show" them :o)))

This is the input voltage and current:


I measured the power factor tonight at 150 to 400 Watts in with a Kill-A-Watt and it was 0.95 :-))) The model seems to confirm that the power factor is indeed very high and the coil is very "friendly" to the AC line ;-))

The power on the 1k 100W caps is now known:


0.45^2 x 1000 = 202 watts. Hard to say since the voltage is way high and the resistors are fan cooled. But nothing terrible there. Prolly should just use 225W one and make it a "don't care" ;-))

Weeeeeee!!! Now that I got a computer model, I don't have to run the real coil anymore!!! :o)))))))))




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):


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:





There is a VCD format movie here:


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


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!!!