Magnifier Calc.'s Discussions
Edited/Updated: October 23, 2004
Resonance, and now magnifiers Discussion
1) Richard Hull has some tapes on his magnifier research and has reported coupling coefficients of over 0.50 and I believe he either hit or
slightly exceeded 0.60, I'll have to review those tapes, but those numbers are
probably contemporary records for a magnifier and really do point out the power
processing abilities of a well built magnifier. Tesla migrated to his magnifier
design due to this greater efficiency.
2)
0.6 is the maximum for a regular Tesla coil. Magnifiers can easily work with
more, but this is not common. The tight coupling between primary and secondary
is fundamentally a compensation for the the presence of the third coil, that
lowers the effective coupling coefficient of the system.
Some examples of fast magnifier modes:
Mode: L1-L2 Coupling:
1:2:3 0.6741998625
2:3:4 0.4633831313
3:4:5 0.3504383220
1:2:9 0.7666721982
2:3:14 0.6111887907
3:4:21 0.4555734516
The "mode" is the ratio between the resonance frequencies of the assembled
system, that are three in a magnifier, if the capacitance across the secondary
coil is considered. The first three modes in the example require high
capacitances across the secondary coil. Are the most efficient for energy
conversion, but may not be the best for spark generation. The three last modes
require low capacitances that can be distributed, and look more as the
magnifiers built empirically for spark generation. A program that can
design and plot waveforms for magnifiers is my mrn6 program, available at
http://www.coe.ufrj.br/~acmq/programs
See also the programs optmag and the older magsim.
Antonio Carlos M. de Queiroz
3) Original poster: "john cooper"
<tesla@tesla-coil.com>
In a magnifier, you want the tightest coupling possible, i.e., a solenoidal
primary. That doesn't mean that other primary configurations won't work but the
magnifier's main reason for being is its power processing capability.
4)
Not necessarily the "tightest possible", but any reasonable design ends with a
quite high coupling.
See:
http://www.coe.ufrj.br/~acmq/tesla/magnifier.html
Just to verify, I can use the Inca program to calculate the coupling coefficient
between a flat primary coil and a flat secondary coil that continues it, forming
a disk. Let's suppose a primary with 10 turns with maximum radius of 50 cm and
minimum radius of 25 cm, with a secondary coil with 1000 turns with the shape of
a disk inside it,
with a radius of 24 cm. Wires with 2 mm and 0.2 mm.
Inductances: 0.l mH and 167 mH
Coupling coefficient: 0.294
Not very tight, but enough for a magnifier operating close to mode
4:5:6.
Antonio Carlos M. de Queiroz
5) Original poster: David T.
I did some research with flat spiral coils while replicating Tesla's work with
his Wardenclyffe project.
http://www.tesla-coil-builder.com/FlatSpiralSecondary.htm
In particular, I did experiments with combination flat spiral and solenoid
secondaries.
http://www.tesla-coil-builder.com/tesla_magnifier_1.htm
I found that changing the geometry of the coil changes the properties of the
charge. A solenoid coil will produce higher potentials and is good for
developing electrostatic charge. A flat spiral coil will develop higher current
and magnetic field and is good for developing electromagnetic charge.
Since most Tesla coil builders are only interested in the long sparks, a pure
solenoid coil is the only way to go. However, if like Tesla you were interested
in generating powerful electromagnetic pulses, you would use the flat spiral
coil. The Wardenclyffe tower was a combination of the two types of coils in the
secondary and was coupled with a solenoid or conical primary. The top
capacitance of Tesla's system was designed such that the ac charge would just
reach maximum before breakout, and then the full charge would be fed back down
into the flat spiral portion of the secondary. This amplified the
electromagnetic pulses that Tesla sent through the Earth's negatively charged
surface via the extensive ground system Tesla built. In effect, Wardenclyffe
was a huge sledgehammer where the hammer was made from electrons. By beating
the Earth with this sledgehammer Tesla was able to cause longitudinal ripples in
the Earth's negative charge. When the ripples were strong enough to encircle
the planet and reflect back to the sledgehammer, the sledgehammer would need
progressively smaller blows to keep the longitudinal waves at full
resonance. By coupling to the potential in the nodes, Tesla had hoped to
receive power at a distance.
Unless you are working with electromagnetic pulses, a flat spiral coil is not
very useful for Tesla coil builders. Just as the solenoid coil produces
greatest action when the electrostatic potential is highest, the flat spiral
coil produces greatest action when the electromagnetic current is highest.
This means that flat spiral coils, per length of wire, cannot generate the high
potentials of a solenoid coil. High potential is necessary to produce a long
streamer. Although coupling is important in determining spark output, coil
geometry is also important in order to fully take advantage of the
electromechanical properties of the electron. Dave
http://www.coe.ufrj.br/~acmq/tesla/magnifier.html
Transmission lines
Date : Wed, 21 Jul 2004 07:21:13 -0600. Subject : Re: Resonance, and now magnifiers
Original poster: Bert Pool
<bert.tx@prodigy.net>
At 09:08 PM 7/20/2004 -0600, you wrote:
>Original poster: DRIEBEN@midsouth.rr.com
>Bert,
>
>I think I've seen your magnifier on your webpage and noticed the 12" wide
aluminum flashing transmission line. It seems that you would have trouble
with corona losses along the edges of the flashing, considering the thinness of
it. I was just wondering how you dealt with this or if corona was even a
problem?
>David Rieben
David,
There is absolutely no corona. Photographs with exposure lengths of several
seconds should show any corona and they show none. What is interesting is that
you would expect corona loss on a transmission line to
seriously affect spark length. At our last Teslathon, we used the aluminum
flashing in one test, followed by a two inch diameter aluminum pipe, and finally
a 24 gauge wire as a transmission line in a third test. The small diameter wire
had about a 2 inch diameter corona down it's full length, but in no case did we
ever see a measurable or visible difference in spark output. It's almost as if
the corona down the wire forms its own conductive plasma channel. Considering
the high voltage at the top of the secondary, I/R the losses down a moderately
resistive plasma channel would be insignificant, yes? Bert.
Date : Tue, 20 Jul 2004 21:08:51 -0600. Subject : Re: Resonance, and now magnifiers
Original poster: "Dr. Resonance"
<resonance@jvlnet.com>
With maggies another nice transmission line can be formed with some 4 inch wide
flat copper strip that is siliconed onto some 8 inch wide flat acrylic
plate. The copper strip is attached to both sides leaving a long conductor with
very low inductance. Dr. Resonance.