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Re: Sold state IGBT disruptive coil spark gap idea (SISG)

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi All,

Today "all" parts or "in" for my SISG :-)))

I have been testing/experimenting with the thermal epoxy:


Figuring out all it's secrets.... Silver filled two part epoxy is tricky in trying not to smear it into HV areas (for HV, it is VERY conductive!!). The contact area is only like 1/2 square inch at say 2 mill thick. So it only takes a tiny drop about 3 mm diameter x 1mm high... Once it get to the edges it stops in a bulge. So I am testing it on a SUPER TO-247 SCR first. Looks great!!! But not a "beginner epoxing" project... I should make "instructions" on how to do it just right...

I see Mark and DC came back with two "different" answers on the ballasting =:O But I got the "universal" solution ;-))


50 ohm variable 250 watt resistor... As long as it does not really "go up in flames", it is "just fine" ;-))) I can figure out the low loss inductive things "another day"...

The "rev d" boards are fine:


I did make one little correction for the top 1Meg resistor going across an HV trace in that latest ExpressPCB file:


I just spaced the resistor 1/8th inch above the board here. The new file fixes that. I am going with the NASA idea of using old proven hardware with minor tweaks since it can't go "too wrong" ;-))) Mark will have far nicer boards soon anyway...

So hard at it...  But probably just gluing sinks to IGBTs for now...