New Baby!!! SISG!! 2:52PM (MST) weighing in at 0.78 Oz / 900Volts at 800 Amps!!!!!!

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Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

The SIDAC/IGBT Spark Gap "SISG" was BORN today ;-))

Here is the first picture:

http://hot-streamer.com/temp/SISG-Born.gif

The inductor was 634nH, thus the fast ring down, (like a dead short 
jumper wire) ;-))  260kHz with 600nF of capacitance firing at 900V.

"800 Amps" at "0.05 ohms" effective resistance ;-))  In most cases, 
even the SUPER TO-247 will not need a heat sink ;-))  Mark at 460 BPS 
will need little ones ;-))

Hehehe!! just scope pictures, but no "sparks"...  But us "scientists" 
now that the "sparks are trivial now" :o))))

The modules work in series just fine and a single module can be "way 
overloaded" with NO apparent damage!!  I drove 700 amps through the 
old one many times and it lived just fine...

More pics here:

http://hot-streamer.com/temp/SISG-001.jpg
http://hot-streamer.com/temp/SISG-002.jpg
http://hot-streamer.com/temp/SISG-003.jpg
http://hot-streamer.com/temp/SISG-003.jpg
http://hot-streamer.com/temp/SISG-005.jpg

Note the extra kludged on components...  I thought getting ride of 
the wire inductance on a "real PC board" would fix the gate voltage 
going too high problem.  But not quite at 800 amps =:O

http://hot-streamer.com/temp/SISG-Born-GateOverdrive.gif

35.6 volts on the gate is not terrible... But adding another TVS (I 
guess "transorb" is "old now"...) to the gate would fix this and 
probably make the module more "streamer hit proof" if it got hit.  I 
wondered too, if it was just probe error being near an 800 amp 
signal...  So I got a 20V and 15V TVS and added them to see:

http://hot-streamer.com/temp/SISG-Born-GateOverdrive-Clamped.gif

It is nice to know that those $1200 probes really do work perfectly 
:-)))   The extra transorb - Opps... "TVS" clamps the voltage right 
on and does not hurt the turn-on margin at all...  So it is a new 
part now...  That emitter inductance is a "real thing"....

Close ups of the on resistance:

http://hot-streamer.com/temp/SISG-Born-VI.gif

The current through and the voltage across the gap.

A calculated dynamic resistance (three ways)...

http://hot-streamer.com/temp/SISG-Born-VI-Calc.gif

But everything comes out to 0.05 ohms or maybe 0.046....

That is "60 times" better than a regular spark 
gap.  HAHAHAHahahahaha!!!!!!  Gerry, the gap resistance number is now 
0.05 ohms...

The new schematic is here:

http://hot-streamer.com/temp/SISG-Schematic.gif

The IRGPS60B120KDP is a very impressive IGBT!!!!!!  It has "more 
active area than a cow"...  and "costs" more than a "cow" too $:O  I 
expect them to be hard to get if history holds...  DigiKey had 50 on 
the self for months....  In the last day... They got 12 
left >>:o)))  Thank goodness I got "mine" ordered five minutes before 
I posted this  >>:o))))  After the Panasonic and CE cap thing, "I" 
know that game ;-))

The SISG does not "quench" (yet...) but with 0.05 ohms of resistance, 
all the energy is "safe and sound" in the primary circuit ;-)))

I hope to get a full and high voltage SISG going "real soon" that can 
run almost any coil...  You can tap the voltage you want in 900V increments...

Even "I" am "stunned" by all this...  Things really have "all changed now"...

Cheers,

	Terry

BTW - It is all "Public Domain" with no string attached...  So party 
hardy :-)))