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Re: HV Arc Resistance
In a message dated 99-07-13 05:28:37 EDT, you write:
<<
> Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
> Perhaps I'm missing something. If a rotary gap fires 1/4 inch before
> electrode alignment, of what value is close electrode spacing? It seems to
> me that arcing distance is determined by electrode radius of curvature and
> Vcap, and that aligned-electrode-spacing wouldn't matter, since quench would
> probably have been achieved before alignment.
> Regards, Gary Lau
> Waltham, MA USA >>
Gary, all,
One advantage is that the gap is becoming (slightly) narrower as it
fires, thereby lowering the gap resistance. I suspect too that the
whipping air tends to disrupt corona streamers around the electrodes,
and delay the firing perhaps? I agree that it's best to prevent
early firing as much as possible. To prevent early firing, I like to
round off the tip of the electrodes to create a hemisphere shape, which
hopefully increases the hold off voltage and permits the gap to fire only
when they are closer. I think the hemisphere should be somewhat flat
in the middle to give a large surface area for cooling however. I
remember you did work with the pipe electrodes, and other schemes
which give a similar result.
Cheers,
John Freau