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Re: More: 120 bps vs. 240 bps comparison tests
In a message dated 99-05-31 05:27:48 EDT, you write:
<< Original Poster: John Williams <jwilliams-at-edm-dot-net>
> My two cents for what it's worth:
John,
What you say below is correct, and are well known Tesla coil
phenomena. I was trying to quantify just how much of a spark length
gain is produced by this "growing of sparks" effect by comparing
various break rates. There's no doubt that the sparks are lengthened
by repetitive re-ignition of ionized trails, and that the overall spark
length depends on voltage and current at the terminal, break rate,
and power throughput. These effects have been discussed extensively
on this list and elsewhere in the past. Thanks for your comments and
observations.
John Freau
> I thought a while ago that there was a relationship
> between the frequency of commutation of the tank circuit and
> the length of the spark if all else was equal.
> My reasoning was that the sparks we see from these
> things aren't single strokes but several happening together in
> a short space of time. Take a close look at a time exposure of
> a tesla coil discharge and you'll notice a banding effect like
> someone had drawn wavy lines parallel to each other.
> They come from the action of the discharge. It is
> a series of pulses not a single dancing stroke.
> So the discharges strobe.
> Same thing happens in a lightning stroke. Lightning
> isn't a d.c. pulse either folks.
> Ok...
> Each time a breakdown occurs it leaves behind an
> ionized path that starts to dissipate. The next time the gap
> commutates the energy will tend to propagate along the
> pre-ionized trail left from the previous breakdown.
> It's as though you were trying to shatter a piece of
> glass that was self healing. You hit it once and create a crack
> and as you draw back to hit it again it starts to close. If you
> hit it fast enough you can build on the remnant of the first
> crack. If you don't you just make the same size crack each
> time.
> A aquaintance of mine has a floor standing coil
> that procduced free air streamers of a bit over five feet in
>length. He was running a salient pole synchronous motor
> on his gap with eight poles at eighteen hundred rpm.
> When he went to a thirty-six hundred rpm
> synchronous motor his arcs grew out to six feet and some.
> He didn't change anything else that I know of.
> I suspect that Tesla Coil spark length is the result
> of a combination of potential at the terminal capacitance,
> available current at the terminal capacitance, frequency
> of commutation and average power through put of the
> system.
> In simpler terms it is the power per pulse and
> how often you deliver that power that governs the
> true length of the streamer. Not raw potential alone.
> Just a thought...
> John W.
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