I have some pics of my SISG twin setup here: http://tesladownunder.com/SolidState.htm#TwinSISGSparks are only 80cm though from two 50 cm coils. I am aware that my small spherical topload and rather high res frequency coil are limiting output but there is another problem as well. The problem seems to be the boards are not firing at 3.6kV. I measured the firing voltage of each board (out of circuit) and they varied from a low of 1.8kV to 2.4 and 2.9kV. Total firing voltage of 5 boards is less than 10kV rather than 14kV. This suggests that something is wrong on all the boards but I haven't localised it to the SIDAC or IGBT level yet. Or something else like the SIDAC voltage equalising resistors. Maybe I blew something earlier when I had a brief try on a smaller coil and the SIDAC's got hot. But some of the boards were virgin before being used in this setup. It worries me a little that Terry said that firing was erratic and that he had to have 100pf bypass caps in various places as a stability thing for MicroSim. I wonder if some capacitative coupling between boards might not be occurring resulting in premature firing. I say this because initial firing is at 140V out of 260 on my variac but firing does not stop until the variac drops below 120V. Really, I should barely have enough voltage at 260V.
Peter----- Original Message ----- From: "bartb" <bartb@xxxxxxxxxxxxxxxx>
Hey Peter, Yeah, kind of old pics also (just showing the board mainly). It's all been re-arranged a little (no rotary inside any longer either). Can't wait until you get some pics up. BTW Peter, my SISG is not the best in spark length. This I believe to be due to using a low C value (very different than any other SISG I'm aware of). Food for thought. Take care, Bart
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