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Re: Slow Wave Helical Resonator Experiment

Hi Terry,
          I can confirm what your computer model says as I have done 
exactly that in a real experiment:

> Original Poster: Terry Fritz <twf-at-verinet-dot-com>
> 
> Hi Antonio,
> 
>     Many thanks for pointing out my error in assuming the gap stopped
> conducting during a primary current notch.  I have read that paper many
> times and I always just assumed it quenched where all other Tesla coil's
> quenched.  I have a high-speed fine-tip multiple-quench (up to 16 gaps)
> rotary gap here.  I will try to redo this test and attempt to break the
> primary current during the peak of the cycle.  I don't know if I will be
> able to do that or not but I have just about the best equipment available
> to try it with so...  
>     I ran the situation through my computer model (the computer can quench
> whenever it wants :-)).  The secondary voltage was at zero during the break
> in the primary current and just stayed there.  The primary voltage across
> the gap spiked into the 200kV range as on would expect in breaking the
> primary inductor current but the secondary voltage showed no change.  So
> the computer does not predict what the paper says.
>     I will see what real testing can determine and report what I can find.
> 
> Thanks,
 
>     Terry Fritz
>     terryf-at-verinet-dot-com

I performed the experiments with a gap consisting of a bank of 
MOSFETs. I could quench anywhere I liked in the cycle which an 
ordinary gap cannot do. Quenching at a zero current crossing (peak 
cap charge for whatever energy remains in the primary) resulted in a 
quiet quench. Quenching at zero voltage (and current maximum) 
generated the most horrendous voltage spikes across the "gap" (which 
would have reignited a real gap had it dared to go out under this 
condition). I have real scope photos of this which I have posted to 
others. The secondary didn't care a fig where I quenched. There is a 
very simple explanation for this. At the low coupling constants we 
use, the primary flux is mostly coupled to the primary and impresses 
itself back onto the primary.

    There are posts somewhere in the archives detailing these 
experiments from a couple of years back. This was my acid test of the 
Corum's ideas. By using a variable pulse generator to drive the 
MOSFETs, I was able to do anything I desired including investigating 
effects of resonantly charging the primary cap and verifying that LC 
charging ratios allowed primary voltages way beyond the power supply
at appropriately low break rates (somewhere between 5 and 10 times as 
I recall), and I was able to achieve CW running by matching the break 
rate to the resonant frequency and sub-multiples thereof, and finely 
adjusting the dwell time for minimum primary loss. Tesla could only 
dream of being able to do this. 

Malcolm