Re: SSTC theory (scope shots)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Nice clean waveforms Steve.  Can't wait to see the beast at our Teslathon.

Try some 4 sec time delay photos in a dark room at f3.5.  They should look
great.

Dr. Resonance


 >
 > Ive been trying to follow along here though my electronics training (none)
 > sort of hinders things.
 >
 > Anyway, thought some of you may be interested in some tests i did with my
 > original ISSTC.  I decided it was time to try primary current feedback to
 > drive the coil.  So how i went about it was put an 90:1 CT (home made) on
 > the output of my H-bridge driver.  The CTs output drives yet another CT
 > (60:1) to basically reduce the current on the output... mainly so i dont
 > overload my driver board with a lowZ feedback source.  Anyway, it works.
 >
 > A pic of the setup:
 >
 > http://www.hot-streamer-dot-com/srward16/ISSTC/2004_06_29/100_0068.JPG
 >
 > I took some pics with various tunings, but it seems my original tuning
 > (used with secondary base feedback) works the best.  The following is the
 > RF output from the secondary coil:
 >
 > http://www.hot-streamer-dot-com/srward16/ISSTC/2004_06_29/100_0067.JPG
 >
 > This is PRE-BREAKOUT.  You can see that im turning the bridge off at about
 > 7.5 divisions in that picture.
 >
 > Here is what happens when i start to get breakout:
 >
 > http://www.hot-streamer-dot-com/srward16/ISSTC/2004_06_29/100_0066.JPG
 >
 > Notice that the later half of the envelope looks distorted... i think this
 > correlates with when breakout is achieved (i can reduce the burst length
to
 > that point and still hear just a slight crackling).  So indeed the ISSTC
 > system relys on driving lots of *CW-like* power into each spark.  As i
 > turned it up more, it appeared to breakout after just 6 cycles.  Also, i
 > can keep adding cycles to lengthen the sparks, while this is obvious, it
 > seems that this effect was more pronounced with primary feedback than with
 > secondary feedback (but i may need to test this again).
 >
 > Also, this is an older shot of the RF output with secondary base feedback:
 >
 > http://www.hot-streamer-dot-com/srward16/ISSTC/waveforms/100_0074.JPG
 >
 > Note that its a rather linear ring up, but as you begin to really push the
 > power, it looks like the predictions in Antonios paper (fast ring up and
 > levels off for the rest of the burst).
 >
 > Steve Ward
 >
 >
 >