Re: Bare SIDAC vs. SIDAC / IGBT Circuit

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx>

Terry,

This is truly breakthrough work - excellent stuff!

BTW, it looks like the "direct short" you applied through the wire is 
actually a small spark gap (at least for the first ~60 usec). You can 
see the characteristic linear decrement in the yellow trace. The 
exponential decrement from the saturated IGBT shows that it is acting 
more like a (lower equivalent) resistor. In any event, a stack of 
saturated IGBT's should have considerably lower voltage drop than 
even a single spark gap.

By using a directly driven IGBT at the base of the stack, you may be 
able to emulate a triggered/sync gap. And by reducing the gate RC 
time constant (or perhaps by only removing the triggering signal!), 
you may then be able to emulate first or second notch "quenching".

Best wishes,

Bert

Tesla list wrote:
> Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
> Hi,
> Just to follow up...
> I compared the SIDAC / IGBT gap to just shorting across the terminal 
> will a heavy jumper wire.  The SIDAC/IGBT gap was fare better than I 
> could do with a direct short!!
> http://hot-streamer.com/temp/SIDAC-IGBTvsWireShorting.gif
> The SIDAC / IGBT gap is in white and one of my better wire shorting 
> attempts is in yellow.  The smaller the spark when I short it with a 
> wire, the less lossy it is.  But I could never get near the SIDAC / 
> IGBT gap especially in the latter time frame.  The spark probably 
> heats up the contact area cause high losses later on.
> I was using a direct short to judge the SIDAC gap's efficiency.  I 
> guess it is well past 100% now ;-))
> Cheers,
>         Terry