RE: 3 Coil System Was: A photographic tutorial of Pancake Coilwinding...with movies...(fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 23 Jun 2007 20:16:48 -0500
From: David Thomson <dwt@xxxxxxxxxxxx>
To: 'Tesla list' <tesla@xxxxxxxxxx>
Subject: RE: 3 Coil System      Was: A photographic tutorial of Pancake
    Coilwinding...with movies...(fwd)

Hi Bart,

> Most magnifier systems are of the classic design with an 
> L1:L2 driver situated a great distance from L3 and coupled 
> via transmission line. 

Perhaps that is the way most people make them, but it is hardly a property
of the coil.

> L3 is a standalone unit both in mutual 
> inductance and the coil capacity itself with it's topload and 
> ground. Those are completely different beast and follow 
> different design rules which don't apply to this topic.

I disagree.  In the case of a solenoid secondary, yes, it is necessary to
run a transmission line to the third coil to avoid inductive coupling.
However, a flat spiral coil has its magnetic field tilted 90 degrees out of
phase with a thin solenoid connected to the center terminal.  There is no
inductive coupling at all.  As for the capacitive coupling, that also exists
with a transmission line.  At the end of the transmission line, whether
connected directly to the third coil, or connected to a flat plate near (but
not touching) the bottom of the coil, there will be capactive coupling.  The
capactive coupling will only be as good as the resonance matching of the
secondary/primary system to the third coil.

As you have demonstrated to me (intentionally or not), capactive coupling is
the means for driving the third coil in acoustic mode.  

Many magnifier coilers have found that in order to get sparks out of the
third coil, they actually have to be untuned.  If the third coil is
perfectly in tune with the secondary/primary system, standing waves develop
in it that have a high potential at the top load, but no current.  Jeff also
seems to be seeing the same thing when he removes the brass tube.  If he
were to try brass tubes of different lengths, he will find the streamers
actually disappear as the tube becomes resonant with the primary/secondary
system.  When the tube is exactly in tune, he will get no streamers at all,
but will likely get the standing wave coronal discharge I got on my system.

> Very few have built 3 coil systems of helical design as my 
> hybrid maggy. 
> A few of course have with flat coils, but I'd bet in nearly 
> every case, it was similar to your coil in design where the 
> solenoid resonance was determined by the L1 and L2 with L3 
> observed only as a capacity. Trying to get all three resonant 
> through trial and error would be nearly impossible and a 
> program would certainly be needed. Trial and error is very 
> easy with a 2 coil system but not with a 3 coil system as we 
> are discussing.

You are right on this.  That is why I'm going to run some tests to determine
the speed of acoustic waves in electrons for copper and aluminum.  This
information should prove valuable for eliminating the trial and error phase.
Also, cutting a piece of copper pipe to length and then shaving it down to
fine tune it will be a lot easier than winding coils.

Also, it is important we understand that a perfectly tuned third coil will
not produce any streamers.  However, it should produce a strong standing
wave electrostatic field.

> You mentioned that anyone could replace the 3rd coil .... 
> with a pipe of same dimensions and get the same results. That 
> is true only if:
> 1) the 3rd coil is a close proximity coil as L1 and L2 are.

I would bet a transmission line leading to a flat disc would also excite the
third coil if the disc and third coil were in close proximity.

> 2) L1:L2:L3 are not designed to resonance.

I would agree if your intention is to get streamers.  If all three are in
perfect resonance, there will be standing waves on L3, which will be all
potential and no current.  

> 3) L1 and L2 are resonant and L3 is seen as a capacity (which 
> it is when 2 above is not true).

I don't see how L3 will no longer be seen as a capacity just because it is
in resonance.  I think what you mean to say is that L3 will not produce
streamers when all three are in resonance.

> But, if L1:L2:L3 "are" designed to resonance, the game 
> changes, especially in a system with a flat secondary and 
> helical solenoid.

I believe the special result of the exact tuned combination flat spiral and
solenoid is exactly for the reason I stated.  There is no inductive coupling
at the center of a flat spiral because the magnetic field is completely out
of phase with the solenoid.  Therefore, there is no need for a transmission
line.

BTW, I am making progress with your JavaTC program.  It helped me to see
that my capacitor was too big for my present system.  I managed to fix the
IE problem of timing out by following your instructions.  I also managed to
change the default settings.  However, when I changed the default top load
parameters to zero, I got an error when the script booted up.  How do I
comment out the "add_toroid();" line in Java?  Also, what would be the
similar data input lines for the solenoid?

The pupman list is filled with an abundance of good information and tools
for coilers.  I made a big mistake not looking into JavaTC sooner.  You have
done a fine job with it.  I'm sure the programs of others are just as good.
I have been working off Ed Sonderman's Excel sheet for the past ten years.
It was good for its time, but your program is so much better.

Dave