Re: Static Spark Gap

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Rob Judd by way of Terry Fritz <teslalist-at-qwest-dot-net>" <canska-at-a5-dot-com>

 > Original poster: "Mccauley, Daniel H by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
 > How do you figure on 200 BPS???
 > I would think that with a static gap, the primary tank circuit is going to
 > charge up at 2 * 60Hz (positive and negative
 > peaks of the input 60Hz voltage) and static gap would discharge at some
peak
 > of these positive and negative peaks.
 > My calculations would say 120 BPS.
 > What am I missing???
 > The Captain

As far as I can tell, its rare to get a perfect 120BPS. The gap is going to
fire whenever the voltage is high enough to ionize the air. The tank cap is
going to make the biggest difference (depending on whether it is STR, LTR,
or exactly resonant). Other factors I've noticed are the physical parameters
of the gap unit, such as the copper pipe length, mass air flow through the
gaps, and the current from the high voltage supply. All of these affect how
quickly the gap can quench, and the longer it takes to quench, the longer it
takes the tank cap to begin charging again, and so the lower the BPS. I've
noticed a subtle (but easily detectable) difference in BPS with changes in
temperature, humidity, and barometric pressure. That makes sense since these
factors affect the breakdown voltage of air (ie the hotter the electrodes
are, the lower the firing voltage and therefore the higher the break rate).
So, although I'm certain a static gap could be engineered to provide very
stable and predictable BPS, an RSG seems the easiest way to get that kind of
control.

 >From the scope readings I've taken from my coil, the LTR tank cap seems to
fire 3 to 5 times per 60Hz peak, a break rate around 360-600. Looking at
Richie Burnett's site, it seems I'm not the only one to have seen this...
http://www.richieburnett.co.uk/static.html In fact, he explains it much
better than I just did :-)

Rob Judd - canska-at-a5-dot-com