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Output Voltage vs. Firing Rate (fwd)



---------- Forwarded message ----------
Date: Mon, 3 Aug 1998 21:46:29 -0600
From: terryf-at-verinet-dot-com
To: tesla-at-pupman-dot-com
Subject: Output Voltage vs. Firing Rate

Hi All,
	We were having a little Colorado Tesla meeting on Sunday.  I noticed that
my gap seemed to give better sparks when the gap was set to a lower voltage
than maximum.  In other words, The streamers were longer with lower gap
voltage settings.  Modeling shows that this is probably due to the fact that
the firing rate probably increased by a factor of three from 120 Hz to 360 Hz.
	I have always tried to design coils to create a very high output voltage.
However, Sunday's experiments would suggest that we need a higher firing
rate ( >120 Hz ) also.  In fact, one may need to sacrifice substantial
output voltage to increase the firing rate to get the best streamers.  My
latest gap design will be able to explore this realm in far greater detail.
I suspect that once the output voltage is high enough to cause breakout, we
need to use firing rate the push the streamers out rather than pure voltage.
High voltages tend to cause many short streamers while high firing rates at
lower voltage tend to create a single but much longer streamer.  Obviously,
this subject is very important to our endeavors.  
	My next gap design will allow easily adjustable voltage, high power, and
very good quenching that should allow for very optimal adjustments of these
parameters that seem important.  If anyone has any input to such issues
please let me know.  
	I was very impressed with Dave Burman's vacuum gap.  I never have used much
airflow before but there seems to be a substantial advantage to having a lot
of high-speed air flowing through the gaps.   Not only does air improve
quenching but it also aids cooling.  With a little larger pipe and much more
airflow, my present gap design can be greatly improved.  Hopefully, a static
gap could handle very high power levels and still give excellent quenching.
I suspect that the firing voltage can be carefully adjusted to give the best
output potential and firing rate in order to produce the longest streamers.
There is probably a "sweet spot" between these two factors.

	Terry Fritz