Re: 12 MV 100 years ago

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

Original poster: "Peter Terren by way of Terry Fritz <teslalist-at-qwest-dot-net>" <pterren-at-iinet-dot-net.au>

Hi Malcolm
Thank you for taking the time for the extended explanation which is now
mathematically clearer to me . I have looked up your posts of around 9/5/03
which were also helpful. I had read them before but the significance didn't
sink in at the time.  My Vpeak is therefore around 400Kv after losses (and I
will eat humble pie and adjust my website information accordingly). I do
suspect that each of the the predicted theoretical Vpeak and the formula of
John Freau (power vs spark length) and the direct observations and formulas
of John Couture (spark length vs voltage) are not contradictory when
compared with the data from which they were generated but extrapolating away
from those data with different break rates, toroid construction and extreme
voltages will result in significant differences. The apparent lack of clear
TC instantaneous voltage and spark length data will still leave this area a
bit muddy.

In regard to your coil I put forward a separate posthulate to explain a
proportion of 1 bps (11inch) to 120bps (60inch) difference in spark length .
Spark formation in both the spark gap and streamer formation is subject to
variation in length for a given voltage particularly with a disruptive
system. Factors could include local ionisation, air turbulence (= low
pressure), nonuniform RF field factors and temperature. Variable breakdown
in the spark gap will result in variable bang energy for example. If you
choose the longest spark from N=1 beats and compare this with N= 7200
(120bps * 60 secs) then with a normal distribution of spark lengths you are
likely to have a longer spark with the higher bps. In support of this I have
noted that in normal TC use I don't observe continuous sparking off the
toroid until the spark length is significantly less than half the peak
length although an amount of this difference is due to my ARSG. I would be
interested to know if this is also the case with an SRSG. A fairer test
would be comparing 7200 single shots with 7200 in 1 minute and with perhaps
more objective confirmation of peak primary cap voltages in each scenario.
Despite this posthulate, I suspect it only accounts for the smaller
proportion of the differences noted but I would be interested in other
opinions on this variablilty.

Peter (Tesla Downunder) http://members.iinet-dot-net.au/~pterren/

 > The first point to make is that maximum theoretical output voltage
 > for a disruptive coil is well-defined. <snip>
 > To take
 > an example that I will repeat for the second time in a fortnight, I
 > have a coil whose theoretical Vout is about 370kV. In reality it is
 > less because of losses. I expect it to be closer to 300kV and the
 > fact that I can get connected sparks approximately a foot long when I
 > operate it in single shot mode is indicative. However, when I bump
 > the breakrate up to 100 - 200 BPS, the sparks will stretch and
 > connect with objects over 5 feet from the terminal. The output
 > voltage has not changed - the gap still fires at about the same
 > voltage being a fixed static type, but the sparklength has increased
 > fivefold.
 >
 > The point is that there is a strong correspondence between power
 > fed in and sparklength but only a weak one at best between voltage
 > ans sparklength in normal repetitive operation.

 > Malcolm