Re: LC III

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>



Transmission line theory did have some application in very early coils where
they were just running 1-2 inch dia toploads and long, skinny coils.  Also
vac tube coils with their long 2 inch dia. skinny coils did seem to apply to
TL effects.  They were essentially "ham radio antennas" with a small
capacitive hat topload.

TL theory, as Paul & Terry correctly point out, has nothing to do with large
dia coils and huge toploads.

Dr. Resonance


>
> Transmission line theory was popular in the 80's especially with the
> Corums.  But I never saw an example where they actually got the analysis
to
> work...  They were on the right track, but the devil was in the
> details...  The true system was too complex...  The Tesla coil is a very
> "non" uniform transmission line and the coefficients one comes out with
> look pretty much like a simple inductor or an impossible mess....  It fell
> apart in the 90's and was replaced buy lumped parameter models which are
> still often used.  Today, computers can grind fantastic amounts of data to
> really get down to the true operation of the Tesla coil.
>
> http://www.classictesla.com/fantc/fantc.html
>
> I don't think anyone even tries to study coils with transmission line
> theory anymore even with fancy computers.  All the modern programs and
> techniques either are lumped parameter and Medhurst based or use finite
> element analysis.  There very high accuracy is undeniable!!
>
> I think transmission line theory's last days are summed up in these two
> pieces from five years ago...
>
> http://www.ttr.com/corum/index.htm
>
> http://www.pupman.com/listarchives/1999/October/msg00428.html
>
> So I join with Paul (but perhaps with a bit more gentle tone ;-)) and
agree
> that if your still trying to use transmission line theory with Tesla
coils,
> your 10 - 20 years behind...
>
> Cheers,
>
>          Terry
>
>
> At 06:22 AM 3/27/2005, you wrote:
> >Jared wrote:
> > > you are misapplying transmission line theory.
> >
> >No I'm not.  You're ignoring all the evidence of measured
> >coils, and apparently can't be bothered to learn any of the
> >relevant theory.
> >
> >Have you measured a coil yet?  Your faulty assumption of light
> >speed propagation along wires will put you around 50-100% out
> >on frequency measurements.  Measure a solenoid and see that you
> >are wrong and EM theory is correct.
> >
> > > This is the likely reason for the accuracy of our model in
> > > predicting node locations in multiple wave length coils.
> >
> >Again we see the bottom line of your argument - the nodes
> >are in the right places.
> >
> >Let me use a rope analogy.  Vibrate a rope between two anchors
> >to form some high resonance with multiple half waves, and note
> >the node positions.  Then, increase the rope tension so that
> >the propagation velocity is increased.  Set the rope oscillating
> >once more in the same mode (now at a higher frequency).  The
> >nodes will be in the same locations.   In the same way, your
> >observations of node locations say nothing about the propagation
> >velocity.  You saw the nodes where you expected them and
> >erroneously concluded that the operating frequency and velocity
> >must therefore be as predicted - an elementary mistake.
> >
> > > it does bother me that you would describe velocity factors of
> > > up to twice the speed of light, pretending that this was some
> > > sort of mainstream science.
> >
> >If you'd bothered to read earlier extensive replies attempting
> >to correct your errors, you would already understand that a
> >velocity factor with respect to the wire of greater than unity
> >doesn't imply that signals are travelling the wire at greater
> >than light speed.   It shows instead that the field disturbances
> >we call "signals propagating through the coil" are guided by the
> >wire into a spiral with a pitch greater than that of the winding.
> >
> >If it makes you happier, define a velocity factor with respect
> >to the solenoid length instead, to get factors around 0.001
> >or so.
> >
> >This is just an example of a much larger class of phenomena in
> >physics in which EM propagation velocity is reduced (sometimes
> >severely) in the presence of charged particles, both free and
> >bound.  Inside a metal like copper, for example, the velocity
> >is down to walking pace!
> >
> > > Richard Quick told you this about 10 years ago, you should have
> > > listened to him.
> >
> >He's never told me anything. What on earth are you talking about?
> >
> > > The rope resonance models we have employed are not jokes.
> >
> >Sure, rope models are handy, sometimes.  But they don't have the
> >properties of an EM field.  For example, each piece of rope only
> >affects its immediate neighbours, via tension, whereas charges in
> >a wire affect each other at a distance via their fields, especially
> >so when they are brought into proximity by coiling.  All those EM
> >effects are missing from the rope model.  They determine the
> >inductance and capacitance and propagation velocity, taking the
> >place of tension and mass in the rope model.
> >
> >If you push the rope analogy too far, you end up with predictions
> >for a rope, not a coil!
> >
> >Please, measure some coil frequencies before you make more of a
> >fool of yourself.  Then go learn the theory that predicts those
> >frequencies.  Otherwise, people will laugh at you for ignoring
> >measurements and rejecting well established theory - all because
> >you are too stubborn to recognise that you made some elementary
> >mistakes.
> >--
> >Paul Nicholson
> >Manchester, UK.
> >--
>
>