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Re: Base current......Re: Tesla Coil RF Transmitter

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

At 10:18 AM 9/15/2005, you wrote:
I am going to cautiously disagree with what you are saying. I have looked over the websites you pointed me to, and I see a couple of issues.

1 -- The tssp website says that it is trying to model real life coils in software, and trying to predict them as close as possible. Somewhere in there it says the inductance of a resonant coil cannot be predicted by lumped element formulas, as the current is not uniform along the coil

The tssp program calculates secondary currents with very high accuracy directly from physics theory using large numbers of calculations. There are lumped parameter models that us well known "fudge factors" to also get very good accuracy (Medhurt's formula). The lumped parameter models can easily find the fundamental frequency, but cannot find the higher order resonances.

The lumped formulas are fast and easy for finding Fo. The tssp models are very good at finding everything else... Todays computers are now fast enough that direct computation is getting to be "easy".... TSSP has provided us with the basic tools for direct computer calculation.


2 -- The GeoTC library clearly states that it calculates the inductance from Grover's tables. I have looked at the actual source code, and this is indeed the case. Inductance calculations are done by sepparating a coil into individual turns, and then looking up the inductance in grover's tables for that turn. As stated elsewhere, inductance of a resonant coil cannot be predicted on the basis of tables.

Wheeler's formula is very good at finding the inductance of a coil, but it is an empirical formula derived from test "results" only. The newer programs can now crunch the numbers to find inductance from direct physics.


3 -- GeoTC does not seem to be a full implementation of tssp, rather a library built on some of the concepts of tssp (their words, not mine); therefore, just because tssp may be accurate, does not mean GeoTC is accurate. As a matter of fact, since GeoTC calculates top load capacitance, and coil inductance, and derives resonant frequency from that, it seems it is indeed considering the TC as a lumped element circuit, which was disproven by J. & K. Corum.

I think GeoTC is a subset of the computer programs derived from the tssp project and they are all based on the same principles and written by the same person. the new version is just optimized for speed and in a nice sub function form.

I disagree with the Corums there. But that whole argument is now getting dated...

http://www.pupman.com/listarchives/1999/October/msg00428.html


4 -- one final note: without any sparks comming out the top load, how can the current be uniform? for a current to exist, there has to be, excuse me for repeating myself, an actual CURRENT! since the top load only sees a voltage potential, there can be no current at the top. If your software is telling you that the current is evenly distributed, there is something wrong with the software...

We are basically charging and discharging the top of the coil which is say a 30pF capacitor. If we charge a 30pF cap at 200kHz to 500kV... the current is:

I = V / R = 5e5 / (1/ (2 x pi x 2e5 x 30e-12)) = 18.85 amps peak or 13.3 amps RMS.

Cheers,

        Terry




Dan


----- Original Message -----
From: <mailto:tesla@xxxxxxxxxx>Tesla list
To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx
Sent: Wednesday, September 14, 2005 7:34 PM
Subject: Re: Base current......Re: Tesla Coil RF Transmitter

Original poster: "Dmitry (father dest)" <<mailto:dest@xxxxxxxxxxx>dest@xxxxxxxxxxx>

Hello Dan.

> Original poster: "Dan" <<mailto:DUllfig@xxxxxxxxxxxxx>DUllfig@xxxxxxxxxxxxx>

 > well, let me tell you: if you read Tesla's deposition when he was
 > being sued by the Marconi corporation, Tesla clearly states that for
 > "power transmission" he would run his coil in undamped wave mode,
 > without streamers!

has i ever said that my values are for the case with a streamers
present? not at all.

 > PS.: by the way, are those figures calculated by software, or actual
 > snip..........