RE: Variable Capacitance and Inductance

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Dave,

At 01:20 PM 5/23/2002 -0500, you wrote:
>Hi Terry,
>
>>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 ;-)
>>http://hot-streamer-dot-com/bob/qvar/results/expt8/index.html
>>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 rained that night on the roof.  100% 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?

Nope, not yet.  We need to get that stuff written up better...

>
>Tesla is also saying that the measured capacitance will change over time,
>regardless of which method of measurement or calculation is used.

"i" would disagree that a sphere's capacitance inside a metal shell will
change anymore than a capacitors's value will change for no apparent
external reason.  If the fields are not affected, the capacitance will not
be affected.

>
>>However, his "law" about elevation was overturned on appeal in the supreme
>court of better facts. ;-))
>
>What are these facts you are referring to?

The fact that "elevation" alone is not the reason.  A precision shielded
vacuum capacitor will measure the same value deep in the Earth, on the
Earth's surface, high in the sky, or in outer space.  "Elevation" is simply
not a factor.  You could get the same field change effects moving it
sideways toward a wall.  Reading Tesla words, I don't think he quite
understood that at the time he wrote this.  I don't think he "saw" what was
actually happening there.  But he was very close and soon did latter.

>
>>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.

Paul and I have not written up a nice report yet.  We were exploring what
was making the variations but there have been no real controlled tests yet
to isolate the causes.  There "appears" to be some obvious correlations
however.  Seasons affect humidity and temperature.  I am pretty unconvinced
about the moon ;-))

>
>>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.

I wouldn't give 2 cents for what he was using :-))  I bet he could have
used a nice storage scope and network analyzer!!

>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.

Today we can measure in a second what it took him all day to do.  He could
have gotten a lot more sleep or done other work rather than struggling.
But, of course, history is there and done now...  

>
>>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?

Actually, Paul figured that out not me.  I just fudged it when I had to.
Paul gets the credit for that one!

Cheers,

	Terry


>
>Respectfully,
>
>Dave
>