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RE: TC Spark Energy... THOR vs OLTC ][ + question for Terry



Original poster: Marco.Denicolai-at-tellabs-dot-com 

Hi Steve,

I spent some time at your site today. Very nice job you did!
Congratulations.

 > This strongly suggests that the most important factor in
 > streamer/spark
 > length is simply the amount of energy a coil can store in its
 > secondary/terminal capacitance. (this makes sense, because we
 > know that
 > streamers consume charge in short bursts of high current as
 > they grow.) THOR
 > must have a bigger secondary and toroid, with more
 > capacitance. (Mine is 10"
 > x 30", 1700 turns, with a 8" x 24" toroid. Total energy
 > storage capacitance
 > is around 35pF.)

Differences:

1. At today, Thor is still set to quench after 3-4 notches. You quench
after the first one.
2. Bang size is 20 Joules max. Yours is 2.7 J, right?
3. Secondary + toroid capacitance is 74 pF

 > This suggests that the peak output voltage, waveshape etc,
 > doesn't really
 > matter, the important thing is just to slosh as much of the
 > primary cap
 > energy into the biggest toroid possible.

The only fair way to change something and get a better performance is
just to change the value of the toroid capacitance. Max voltage increase
is 18% but a tight coupling (0.6) is needed. See my paper at

http://www.iki.fi/dncmrc/rsiarticle.pdf

Otherwise you'll change the amount of energy pumped in or the L1/L2
ratio and there will be no point in comparing before and after
situation. An improvement to a 2.0L motor is a replacement with a 3.0L,
right? Not a big deal :)

Then there are the fresh results of Antonio's optimizer program. I
haven't had time yet to investigate on them. In a nutshell they trade
efficiency (amount of charge left on C1) against an higher peak V2
voltage.

But now one question. You are opening the IGBTs after the first notch.
Have you ever tried to quench after it (2nd, 3th, etc. notch)? Did you
experience a derated performance?

Terry, if I recall you can/could do this test. What is/was the result?

Best Regards



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