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Re: SISG Testing/Waveforms

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Mark,

Your getting very good second notch quenching :-)))))

It might be possible to do first notch too. I modified my experimental SISG boards for a R4 pot and (big) 1/4 inch aluminum plate heat sinks:


I can cut the plate aluminum with the band saw and mill it easily enough for perfect custom sinks. The next coil also has "big" fan ;-)) Not sure if I'll make a clamp like you or just continue to use the thermal epoxy... Not too hard just to "mill off" a blown IGBT. But they don't seem to "blow" anyway ;-)))

I am thinking, with some fiddling, one might be able to dial in the first notch. MicroSim disagrees with me, but maybe I can go for second notch at least. It might be much easier at a lower Fo frequency. My next coil is about 134kHz...



At 07:18 AM 7/20/2006, you wrote:

All SISG followers:

Finally got the scope back.
Recall that I was previously getting 1000 BPS with the SISG.
Subsequently, I had managed to increase the transformer(4 MOTs)
impedence(primary side) from ~1.7 ohms to ~8 ohms by re-shunting.  In
addition, I doubled the tank capacitance from 38 to 76 nF. Both had a
significant effect judged by sound and performance.

The new waveforms are shown here:


Now getting 120 BPS which means I am firing near each charging peak.
Using (4) SISG boards or (12) circuits for a threshold 10.8 kV.

Using 680 ohm IGBT timing resistor to get the IGBT "on" time down.

Input VA ~1500
Transformer VA ~1200
Power ~800 watts

Haven't had time to re-tune accurately, but coil runs great anyway.
Need to install a vent fan for the ozone in the basement.