# Voltage/Length (fwd)

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From:  John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
Sent:  Wednesday, January 28, 1998 12:37 AM
To:  Tesla List
Subject:  Re: Voltage/Length (fwd)

At 11:10 PM 1/27/98 +0000, you wrote:
>
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>From:  Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
>Sent:  Tuesday, January 27, 1998 3:35 PM
>To:  tesla-at-pupman-dot-com
>Subject:  Re: Voltage/Length (fwd)

>The closest I have come is to measure single shot attached spark
>lengths (impulse only) as D.C. Cox has done. I have compared those
>with measurements from other impulse sources (Marx Banks) whose
>theoretical outputs can be made to match real outputs very closely
>in practice. The 3'/MV figure is a guide I use although I recognize
>-----------------
The 3 ft/MV at least is a number to work with. In an earlier post Cox said
he thought a 5 ft spark represented one million volts. My engineering text
says that about a 4 ft spark is one MV. But this is a one shot peak voltage.
I would expect that multiple sparks as with  Tesla coil operation would give
a spark closer to 5 ft.
Vs = 65 x 49.8^.7 = 1000 KV
This equation has been used by many coilers and found to be as close as can
be expected to reality.
JC
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>*proven* to be real. This brings us into the realm of model validity
>which is outside the scope of this post.
>--------------------
Model validity is very important and must be capable of being verified by
calculations done correctly. This is especially important when energy,
power, and secondary volts are involved. This is because the Tesla coil
system does unfamiliar engineering magic with these variables. The JHCTES TC
computer program attempts to unravel the intricacies of TC design. As there
are no similar TC programs at present it is not possible to make comparisons
and changes so as to improve it.
JC
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>What calculations? Calculations are trivial if one has a formula but
>having a formula is dependent on formulating for a particular piece
>of hardware.
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Calculations are not trivial when done correctly. Calcs give the facts
rather than subjective opinions. For example the confusion that coilers have
over power and energy could be lessened if calculations of examples were shown.
JC
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>that have no basis in reality. It would appear from what people have
>said that Tuve et al's work is flawed and therefore useless. One can
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How can anyone say that Tuve et al's work is flawed when they do not
understand the fundamentals involved? I would not say that the tests and
calcs of these three scientists were flawed unless I could repeat their
tests and calculations and show where they erred.
JC
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>purpose. Personally, I would accept a quanitifiable error of 1% in
>measuring TC output voltage as being close enough to be useful in
>choosing between models. Jim's technique is a good one in my opinion.
>It gets asymptotically closer to the real answer. It will never get
>Regards,
>Malcolm
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Jim Monte's or anyone's secondary voltage tests and extrapolation have the
advantage that the tests can be easily verified up to 2 million volts. This
is the range of engineering lab high voltage tests that have been published
by several labs in this and other countries. The spark lengths, air
conditions, etc. have been carefully documented. They are all one shot and
not multiple sparks like with Tesla coils. Coilers have found that multiple
sparks are longer than one shots because of the ionization of the spark air
path. The Vs equation above gives spark lengths that are slightly longer
than the HV lab sparks for this reason.

There is a lot to learn about TC operation.