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Re: Safety FAQ is here -- draft, asking for comments.
Hi Robert, all,
I'm afraid I can't agree with your hypothesis....
> I believe that the phenomenon which is being bandied about where some
> people believe that the discharge channel is growing on itself is
> completely illusory and false. I hereby offer my hypothesis.
>
> If we could, through high speed eyes, observe every single
> streamer that rushes out from our toroid, as an individual spark,
> and not confuse it with the one that flashed 2.5 milliseconds
> earlier, or the next one to flash 2.5 milliseconds later (based on
> a break rate of 400 PPS), then I think we would see a streamer
> that exists in a short spac e of time which has one fixed length
> during its entire duration!
>
> In a rotary break powered system, operating on 60 Hz, the system
> capacitor goes through a cycle where it is sometimes completely
> discharged (zero point in the 60 Hz waveform) to where it is half
> charged (45 degree points in the waveform) to where it is fully
> charged (90 degree points in the waveform), and at varying
> voltages at all points in between. Along come the contacts of our
> rotary break, commutating at random, usually half a dozen or so
> places along a 60 hz sinewave. Some commutations will meet a
> fully charged capacitor and the result will be a single pulsed
> streamer for that commutation which is the longest that the system
> can produce. Another commutation will occur at less than maximum
> charge and the single output streamer driven by that commutation
> will be shorter. Since there is a beat frequency between the
> mains rate (or multiples of the mains rate) and the break rate,
> the train of ouput streamers will be formed i n a repeating cycle of
> none, to short, to longer, to longest, to shorter, to sh ortest, to
> none, etc. This is repeated at the beat frequency. When this
> beat frequency is relatively fast compared to the response of the
> eye, like say 10 or 20 PPS or more, and given that the eye
> integrates what is seen (movies and television could not be
> possible without this persistence of the eye), an illusion is
> created where a short output streamer is seen to grow longer in
> steps, aparently building upon itself.
<some snip>
The problem is when you consider the phenomenon using (a) synchronous
breaks, and (b) using static gaps. My large coil with its current
(npi) gap setting produces a streamer about 11" long when operated
single shot, 4ft+ when repetitive. Greg Leyh had some info on this
that you may have seen (although he was using async rotary).
Regards,
Malcolm