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Re: Sync 200BPS improvement, (shorter post !)

Hi Terry, All,
    Have you ever modeled the effect of putting a small capacitor across the
spark gap.  I have been unable to do it myself.  30 years ago in high school
I did some experiments with static gaps.  I put different sized capacitors
across the gap to see if it did anything.  It didn't seem to do anything
signifigant except make the gap run cooler.  I didn't have any instruments
back then to quantify the results.  I was using a 12 kV, 30 ma neon at the
time with a 0.001 uF 12 kV transmitter capacitor in the tank.  Primary was
10 turns of 1/4" solid copper wire, 6" in diameter and 6" high (solenoid).
The secondary was a 2" in diameter by 18" long pyrex glass tube wound full
length with number 32 B&S gauge magnet wire with heavy formvar insulation
(scaled down version of "BIG TC" from the Radio Electronics article).  It
gave 7" branching sparks from a bolt on top only (With no toroid or anything
else. Once tried a 3" ball but it made the spark shorter like a tube coil?).
I tried 50 pF, 100 pF, and 150 pF doorknob capacitors across the gap.  The
output sparks seemed to change a little (more fluidic?).  I did not try
anything higher at the time.  The new MMCs would make such an experiment
very easy with their tap points.

    I know from experience that as the electrodes (and associated
capacitance across the gap and associated field uniformity) get bigger the
switching waveforms get cleaner.  I do not know if the increased gap
capacitance stores energy to help the gap close faster or, as the electrodes
become bigger and the fields become smoother, they can be brought closer
together while holding off the same voltage.  With 4" diameter electrodes
spaced 2 centimeters (0.8" approx.) apart  I could hold off 100 kv in air at
atmospheric pressure.  Interesting possibilities.

    If you try this make sure the safety gap across your transformer is
working and resistively isolated.  The wrong size capacitor could cause
voltage ring up maybe depending upon how wide your gap is set!

Barry


However, non sync gaps are firing at random
> places on the AC cycle.  Thus they are very often firing at less than
> optimal voltage.  > Cheers,
>
> Terry
>
>
>