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Modeling a magnifier




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From:  richard hull [SMTP:rhull-at-richmond.infi-dot-net]
Sent:  Sunday, February 22, 1998 6:52 PM
To:  Tesla List
Subject:  Re: Modeling a magnifier

At 04:26 PM 2/21/98 -0600, you wrote:
>
>----------
>From:  Antonio Carlos M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
>Sent:  Friday, February 20, 1998 4:41 PM
>To:  Tesla List
>Subject:  Modeling a magnifier
>
>Hi:
>
>I was studying how to model a Tesla magnifier, and would like to hear
>comments on my reasoning:
>
>A conventional capacitor-discharge Tesla coil is composed by two resonator
>LC tanks tuned for the same frequency, with the coils magnetically coupled
>with a low coupling coefficient.
>The lumped model for a conventional Tesla coil after the firing of the
>spark gap, and before any breakout of sparks in the secondary, ignoring
>resistances, is:
>
>+-----+     +-----+
>|     | <k> |     |
>C1    L1    L2    C2
>|     |     |     |
>+-----+     +-----+
>
>k is the coupling coefficient, k=M12/sqrt(L1*L2).
>This model works as well as a transmission-line model. The two tanks
>resonate at the same frequency, and the effect of the coupling is to
>produce an "oscillation" in the oscillation, that appears modulated
>in amplitude (DSB) at both tanks, with the energy moving back and forth
>between the two tanks. Periodically, all the energy is in the secondary tank,
>and if the spark gap is quenched at one of these instants (better if at
>the first), the energy is trapped in the secondary, in the resulting high-
>voltage RF in C2 produces the effects that people like to see.
>
>A Tesla magnifier has a transformer with higher coupling coefficient, and
>a separate "third coil" resonator mounted some distance away.
>The ideal lumped model for a magnifier would be:
>
>+-----+      +--L3-+
>|     | <k'> |     |
>C1    L1     L2'   C3
>|     |      |     |
>+-----+      +-----+
>
>k' is the coupling coefficient, k'=M12'/sqrt(L1*L2').
>
>This model is exactly equivalent to the model of the conventional coil,
>if M12=M12', k=M12'/sqrt(L1*(L2'+L3)), L2=L2'+L3, and C2=C3.
>
>As the energy transference only occurs efficiently if both tanks in the
>first circuit resonate at the same frequency, this must also happen
>in the second circuit, when everything is connected together.
>
>The resonance frequency is 1/(2*pi*sqrt(C1*L1)).
>The relation C1*L1=C3*(L2'+L3) must hold.
>The maximum output voltage is VC3max=VC1max*sqrt(C1/C3)=
>                                    =VC1max*sqrt((L2'+L3)/L1)
>The higher coupling coefficient in the magnifier transformer is only a
>consequence of the splitting of the secondary coil. The actual coupling
>coefficient, considering the transformer and the third coil, is as low
>as in a conventional coil.
>
>And this is more polemic:
>The dynamic behavior of the magnifier system is practically identical to the
>one of a conventional coil (with that model, exactly), and so there is no need
>for different operating frequencies and special spark gaps (as I see commented 
>in several places).
>The advantages of the magnifier are that the high voltage terminal can
>be moved away from the primary circuit, and that a more compact and predictable
>primary circuit can be used.
>
>What do you think?
>
>Antonio Carlos M. de Queiroz
>http://www.coe.ufrj.br/~acmq
>
>
>
What is said is partially correct, but vastly over simplified when putting
the things into practice.

  Theory and assumptions based on core knowledge from models, classroom
speak, and thought experiments are abysmally easy because one is at extreme
range,  (galactic distances), from having to touch anything - from having to
really do anything - it saves one from the agony of grubbing around in the
dirt with all the other down at heel folks who are struggling with the
reality of things.

I and a few other s have wrestled with all these issues.  Tesla himself in
1899 noted in his own hand that the primary/secondary (driver)are tightly
coupled for "transformer action" only in order to dump the maximum power
into a system in the shortest period of time. 

 If one simply must insist on radio theory being brought into play on a high
voltage power system and narrows the view to where it has to fit a known
model then yes, the secondary and the extra coil are one single system.
Still, that nasty old reality of experiment shows that the coupling
coefficient as measured with the driver only does not treat it like it is
part of a larger resonator.  It errupts with problems by itself as that is
all the darned flux sees, ever!  The field collapses upon the driver
secondary ONLY and not one line cuts the resonator/extra coil.  If we look
at the thing as a combined broken resonator that is real nice, and the
coupling coefficient plunges from this lofty theoretical view, but..........
and a big but, the equally coupled, smoothly inducted two coil system
doens't act the same at all from a number of standpoints.

Tesla saw this instantly.  The time of loading of the driver effectly
isolates it from the resonator, not only magnetically but resonantly - (this
is assuming the impeadances of the two units are matched and balanced in a
number of very complex ways).  This is shown most boldly by the work of Lou
Balint.  Our own work in Richmond has been in search of output voltage only
and has not struggled with or concerned itself with power transfer or energy
efficiency which does not seem to necessarily have anything to do with
voltage output.

Radio theory is always concerned with power and energy transfer efficiency
only.  They need RF amps, not volts.  They seek to transmitt data at great
range....To lauch an idealized and perfect electromagntic waveform into the
"medium"  We, on the other hand seek to just get volts and thwart the
transmission of any RF energy.  The very signature of a good Tesla system is
that it radiates almost nothing!  The RF (radio) theorists are much more
concerned with the "M" of EMF.  Radio theory is a good place to hang one's
hat while still on the side lines guessing and musing.

Both myself, Dave Sharpe and Alex Tajsek here in Richmond and Ed Wingate in
New York have all testified to the FACT that a fast quench series roatry
will make a tightly coupled k=.6 magnifier system perform very well, where
as the equivalent coupled circuit two coil system falls on its face with the
same gap!!  The series gap sees the k=.6 driver as, oddly enough, a k=.6 and
not as a marvelously harmonious k=.28 equivallency!  Why?  We are still
working on that, but it looks like Tesla was right.  The driver isolates at
the instant of loading regardless of what rings up after the juices starts
roaring through the "system".  The Corums see this but then link the thing
to transmision line theory following resonator fill.  (back to radio).  I
used to like their ideas because they saw the key factor of the driver
ISOLATION, but now I must view the system as lumped in other respects
following the work of Bylund and Balint.

All of us have a long hisotry of two coil system experience and since 1994
the TCBOR has been exclusively mangifier assembly only with 13 different
driver systems, some with up to 7 subvariants (reosnator updates each).  We
do not just mindlessly assemble the same variants over and over, but by
experimentation, improve with each new iteration and move forward with what
is SEEN to WORK!  All of this, not from some magic equation or super model,
but from the DOING.  All these efforts are chronicaled and are now out
amongst the coiler population in the form of video taped evidence with some
60 different two hour taped reports issued since 1989.  John Freau, who has
worked closely with Balint has now open up his taped archives to public
scrutiny.  All tapes openly show patently stupid mistakes, blind alleys,
etc., but also show total success which stems solely from the DOING

Those who do know by their DOING,...understand that regardless of whether
the secondary/resonator/driver/extra coil is just a split resonator or not,
it never, ever behaves as an equivalent single system in the eyes of the
gapping system or the output capabilities.

Magnifiers are not a casually assembled system.  If they were, hundreds of
coilers would be all overtop of them.  As it is, I can number on two hands
the total number of living beings who I feel have a grip on the construction
and the DOING of these systems.

I haven't enough molecules in my body, however, to equal the number of
people who are willing profer advice from afar or on high.  If you must
model, choose one and then build.  Don't sit there and build more complex
models based on book knowledge given by physicists and RF researchers.  How
many of those who wrote the theroy ever built stunningly performing Tesla
systems? - two or three coilers?

Richard Hull, TCBOR