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Re: SISG Testing and Pictures



Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I am "wondering" if Mark's coil has a blown MOT that would explain the "very" high current draw... Modeling says it is not supposed to do that. Only like "sposta be" 15 amps RMS.... He is maybe testing for a blown MOT right now ;-)) I hope the rush to SISG did not blow his coil up too bad =:O Mark's SISG boards are super nice!!! I tested one here and they are "good" ;-)))))

The SISG docs suggest a 4.7K drain back resistor for the gate (R4 in http://drsstc.com/~sisg/files/SISG.pdf). But that is way "too high" in almost all circumstances. The SISG will turn off the IGBTs as a function of the gate drain resistor following this equation:

OnTime = 157E-9 x R4  Seconds

In many cases 2.2k ohms is much better. I am thinking R4 should just be a simple 10 turn trimmer pot so one can easily "just set it to anything"... The times are pretty long since the SISG is very efficient. One must wonder what happens if you set the timing for a first quench notch ;-)) It might work fine!! But the "does" take pots to test out... I have not done that yet... Real busy ;-)))

Too long of R4 time might cause the SISG to "lock on" as Mark was reporting... The SISG might refire way too soon and never stop being "on"... This becomes more critical at higher voltages that might "false trigger" an SISG section....

It has been brought up what about an SISG fired "OLTC" type Tesla coil. Just one "BIG" IGBT at line voltage carrying LOTs of amps... That would be "SUPER" simple ;-)) OLTCs tend not to perform real good, but we have so many "tricks" now!! We can control losses so well now... Might be cool!!! I have never heard of an OLTC coil "breaking"...

So much to do... So much to ponder... The wood stain on my new little coil winder is still drying... Parta are all out till Thursday delivery... Streamer capacitance/foot probably does depend on voltage...

Co=C/l=2*PI*Eo/ln(l/r) F/cm

It is not all getting simpler, easier, or all figured out yet :o))))) But it does constantly get "better" :-)))))

Cheers,

        Terry


At 10:49 AM 6/20/2006, you wrote:

All:

Here are some pics of the streamers from my SISG testing.  Pretty wimpy
at 18" to 24" but better than the nothing I was producing last week from
a blown rectifier:


http://www.teslaboys.com/SISG/SISGStreamers/index.html

Here is the schematic of the coil system:

http://www.teslaboys.com/SISG/TeslaCoilSiSGv2.bmp

Currently using 2.5 SISG boards(10 SISG circuits - Threshold 9000
Volts).

I am still drawing very high VA with a small power throughput.  I am
working on my power supply circuit so that it will work properly with
this new technology.  My power supply used DC resonant charging with RSG
to drive the coil and a number of changes need to be made for SISG.

Mark