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RE: Variable Capacitance and Inductance
Original poster: "David Thomson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>
>At least one person on this list has proposed to run a test over time to
see if there were indeed a variation in inductance in a coil.
>Done that ;-)
>Humidity (especially rain) seems to affect surrounding structures causing
great losses. Temperature affects copper losses directly...
I notice your data is for one diurnal cycle. It would appear from your data
that not only temperature and humidity accounted for difference, but also
the time of day. In the Q factor chart there was a huge drop around 3am.
This is obviously not temperature or humidity related. It would appear that
your data is affected by other factors in addition to humidity and
temperature. Have you run the same tests with the coils enclosed in
temperature and humidity stable containers to compare data?
>Tesla notes that his terminals were very sensitive to surroundings and
elevation. So are ours ;-))
That's the whole point of bringing up this discussion. The parameters of
Tesla coil operation are not contained entirely in the apparatus. They are
machines that interact with many environmental conditions.
>In this article, Tesla seems to have resolved his wire length vs resonant
frequency paradox and he has recognized space charge or Medhurst capacitance
as a factor in his experiments.
Tesla was well aware of self-capacitance long before these experiments. In
fact, he accounts for the self capacitance of the coil in his measurements
>Tesla is correct in his saying that taking the simple capacitance of a
sphere alone is wrong
Tesla is also saying that the measured capacitance will change over time,
regardless of which method of measurement or calculation is used.
>However, his "law" about elevation was overturned on appeal in the supreme
court of better facts. ;-))
What are these facts you are referring to?
>Tesla's stated affects of the moon and seasons have to be severely
questioned as Paul and I's QVAR experiments show.
Your experiments, from what I can see, support Tesla's statements. Do you
have a paper somewhere explaining more of the details concerning your
experiments? What exactly were the conditions of the coils and their
environment? Do you have a data log to share? From what I gather of the
results presented, there were no controls to eliminate temperature and
humidity. If your conclusions are correct, then an identical experiment
with no variation in temperature or humidity would reveal more or less
straight lines. But just the anomalies at 3am show that something else is
affecting the coil characteristics.
>We also have better equipment nowadays. Before you trust Tesla's data too
much, read the part about the type of equipment he was using... Only a
genius like him could have gotten that stuff to work at all!!
Exactly! A genius like him _could_ do it. Our equipment is not better, it
merely exists. Tesla had to build his own LC meters. We buy ours off the
shelf. Considering the values Tesla was generating and the degrees of
accuracy he was obtaining, his equipment was no worse than ours today.
Unlike us, Tesla knew what he was looking at. He could tell, by considering
several different measurements, whether a result was erroneous or not. Most
of us today struggle for want of this type of insight into inductance and
capacitance. We rely on the meters built by others. Accurate meters in
some cases to be sure, but even the best meter is only as accurate as the
person using it. I have seen no evidence anywhere that suggests Tesla's
equipment was faulty or substandard to ours based on the measurements he
took. The results of his efforts are testimony to his accuracy.
>At this time, Tesla did not have the tools to calculate the electrostatic
fields and such around his coils. If he just could have seen the fields!...
it would suddenly have been so clear to him...
Your graphics are good, Terry. But you neglect to fully take into
consideration all of Tesla's tools. Whereas we have computers with CAD
programs and calculators, Tesla had an unusual mind that was capable of
doing the same thing and an impeccable education to support it. Tesla had
entire logarithmic tables memorized. He recounts in several places how he
built all of his motors completely in his mind and how he could turn them on
and off, rearrange the parts, and watch everything as though they were real
images before him. If we are going to judge Tesla's work based on his lack
of computers, we must also judge our own work based on inferior mental
>However, he had to guess and he guessed well.
It is easy to assume that a man without a computer is guessing when we're
comparing to today's education standards. Guessing is akin to crystal ball
reading. Tesla calculated, not guessed. And he calculated well. He could
tell someone what the approximate inductance of a coil would be just by
looking at it. This isn't guessing; it's using the power of the mind to
calculate based on a process and previous experience. An uneducated person
would offer a guess, but not someone intimately familiar with the field.
>Computer programs like E-Tesla, Paul's array of programs, and Rob's new
fastTesla make it all look so easy.
And they are good tools for today's researchers, btw. The ability of us
average folks to network and build upon the successes of each other is a
good thing in itself. It's one way to deal with the abundance of
information available to us today.
>It is interesting to note that our little computer toys do far more
calculations every 1/100 of a second that Tesla did in his entire life!!!
Not all calculations are linear. How many computer programs are creative
enough to discover something not programmed into them and develop the new
concept in ways not before known? Tesla took the works of Maxwell, Faraday,
Hertz, Franklin, Newton and others and developed his theories and inventions
based on previous genius. It wasn't a matter of the number of calculations
that brought success, but the manner in which he arranged his calculations
that played the bigger part of his discoveries. I detect a bit too much
pride in our thinking machines. Although they work wonders, they are also
testament to our mental laziness and incompetence (of which I am among the
>Even if we have only 1/10,000 his brains, we can all out calculate him
:o))) God only knows we do too!! Many of the programs run for weeks on
pretty hefty hardware!!
Forrest Gump comes to mind :-). He had "1/10,000" the average brain and
outran everybody. I don't know that that really means anything.
>I wish "we" had listened to what Tesla was saying in this article since a
lot of time was wasted basing calculations on exactly what Tesla is warning
>BTW - A Tesla coil's measured inductance is different than it's "real
inductance" when operating. This discrepancy was first noted with E-Tesla
where "I" had to guess at things. Paul finally figured it out!
You guys deserve a lot of credit for this work. I have read nearly all the
Tesla literature, and I haven't yet found any reference to suggest Tesla
making this observation. Perhaps Tesla covers this in his blanket
observation that inductance is variable, but he doesn't seem to acknowledge
that the Tesla coil affects its own operating characteristics. Perhaps
someday this will be known as the Fritz/Nicholson Effect?