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Re: [TCML] SISG success
> The coil itself is interesting. I have not seen a decent Q coil using
> 27 awg at 1360 turns before. Q is on the order of 280.
- First I tried a secondary I had laying around:
6.32" by 25.86", 940 turns of AWG 22, about 32 mH and 11 pF
I used a toroid, also laying around:
6.3" by 36.6", about 43 pf
This combination resulted in a spark distance of only 14".
As maximum top voltage is about 0.7 * SQRT (Ls/Lp) * V firing,
increasing Ls will give higher V top. So I decided to copy Terrys
secondary coil. AWG 27 has a "maximum frequency for 100% skin depth"
of 130 kHz and therefore it is sufficient for the operating frequency
of about 110 kHz.
The winding length of 22.8" will easily cope with the expected strike
distance of 42".
> I'm happy to report I am again working on my SISG
- Could you please provide some details/figures?
> I expect I will see dismal sparks as I'm building for an SISG with
> half the C that most SISG's use. Part of my reason is that I want to
> see for myself the results of low C (and work with it before I
> increase it). I will be running 64nF.
- Higher primary impedance will give a smaller peak current. Peak
energy scales as the square of peak current.
> My plans are to charge 3x higher in voltage that your currently
- This higher voltage could compensate the negative effect of a
smaller Cp of course.
> What I'm considering is front end current limiting, to distinguish bps
> regardless of cap size. It will always fire at the same voltage
> regardless, but how fast it achieves that voltage (in my control) will
> determine switching (bps). Yet, I'll be happy just to see it spark at
> this stage in the game.
- Interesting concept! Please keep us updated.
> So no thoughts on how to attain Terry's 42" sparks.
- Maybe the only way to increase the spark distance is to increase
the peak current even more - but this is dangerous of course.
I will try to get the "right" caps and shorting the wires in the
primary circuit will help certainly as well.
Take care of you.
Greed is the root of all evil !
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