Re: Suggestion on Power Supply?

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

Original poster: "Jeremy Scott by way of Terry Fritz <teslalist-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>


 > The spark length is pretty much determined By John
 > Freau's formula:
 >
 > L = 1.7 x SQRT(power)
 >
 > So for 9 foot arcs:
 >
 > 9 x 12 = 1.7 x SQRT(P)  P = 4040 watts input power.

Yep, got that one from my program :)

 > If you want 9 foot arcs you need 4040 watts.  4040 /
 > 15,000 = 270mA as you
 > say.  That would be five 15/60 NSTs but you might as
 > well go for a 5KVA
 > Residential Distribution Transformer (Pole Pig :o))
 >
 > Watts = Joules / second
 >
 > Joules = 1/2 C x V^2
 > Assuming a 15kV transformer, you will get 21000
 > volts peak.  Thus a 30nF
 > cap will have...
 >
 > 1/2 x 30e-9 x 21000^2 = 6.615 Joules for each
 > firing.  Just divide to find
 > the number of firing per second needed to get 4040
 > watts
 >
 > 4040 / 6.615 = 610 BPS

Okay, I think you've lost me ... how does

P / J = B / S ?

Given that a 'break' contains many variables
such as gap resistance, "on" time etc... that
certainly affect the rate and quanitiy of
energy moved.

 > However.........  This would
 > be an asynchronous
 > gap.  It will fire over the average of the voltage
 > not just at the
 > peaks.  Therefor you need to fire at twice that BPS
 > to get the power you
 > need or 1220 BPS

I didn't start at John Freau's formula and work
backwards to obtain the mechanics. Ultimately
I'm not too concered with streamer length as I am
with the overall synergy of the entire system.
(Although, long streamers aren't bad at all!)

I calculated 270mA would be required to charge the
.03uF capacitor up to 21,000V every
8.3333 ms. I would then set my SRSG to fire at
every 8.3333ms, that is, 120BPS -- 90 degrees out
of phase with the 60Hz AC peaks. In order to
accomplish this rate of charging for the capacitor,
a 5KVA pole pig is the closest that will do.
(14400V * .270 = 3.8KVA ) How then, if it takes
8.3333ms to charge the capacitor fully, would it be
possible to do more than 120BPS and still get the
full 21,000V out of the capacitor? (without
upping the supply amperage...)

I would think that the smaller cap/610BPS
combo would lead to many purple short streamers
dancing all around the toroid. High voltage
because the smaller caps charge up real
fast, but not much amperage in each discharge
enough to penetrate any significant length of air.
But plenty of them!

Now a larger cap/120BPS, not as many streamers
as the above...but when they do show up, look out...
long white hot arcs.

All of this is assuming a proper toroid of the same
size in each case. (not too big, not too small...)

Their power both is equal to 4000 watts, one trades
streamer length for streamer quantity, and the other
vice versa... which one do you think John's formula is
based on?



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