Re: expected arc length?

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Steven,

Estimate spark length with a static gap (0.5 PF) is 25 inches.  With SRSG
with 0.9 PF, estimate 34 inches (these estimates assume the spark gap fires
at 21KV).  Your Cp is at resonance for the transformer resulting in about
188 BPS.  If you use 1.6 * Cres (8.33 nf for your NST), the BPS should be
about 120 (it'll run smoother and the gap losses will be lower and you will
have less chance or core saturation and overvoltage).  Estimates are based
on real power processed and JF's equation.

 > Original poster: Steven <studbubba_2000-at-yahoo-dot-com>
 >
 > Given a standard 15kv 30ma NST.  If I built everything else, to best use
 > the available power, what could i reasonably hope for in spark length.  I
 > have gotten 22" arcs with my current setup  3" secondary, flat primary and
 > a .005 mf capacitor with a forced air quenched static gap of .343
 > inches.  Yeah, i hear that the static gap may be too large but it gave the
 > best arc length with my setup....and hey, isnt arc length the goal.

Yes and NO.  Yes you want to max the spark, but you dont want to fry the NST
in the process.  At resonance, the NST output (if allowed) could go above
its output rating by a factor of Q.  You should really set your safety gap
(or main gap if you don't have one) to "just not fire" with no load NST
output voltage and 120 Vac input.

 >
 > And, if someone wanted to suggest a change in secondary or capacitor sizes
 > i would be interested in your thoughts.
 >
 > thanks
 > Steve Lalumandier
 > League City, Texas
 >
 >