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Re: TC Electrostatics (fwd)
Tesla List wrote:
>
> Subscriber: rwall-at-ix-dot-netcom-dot-com Wed Jan 1 21:56:26 1997
> Date: Wed, 1 Jan 1997 17:10:47 -0800
> From: Richard Wayne Wall <rwall-at-ix-dot-netcom-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: TC Electrostatics (fwd)
>
> [Chip, I have observed some of RH's recent electrostatic TC
> experiments. They are incredible and reproducible. Some on the list
> are resistant to new and different developements in TCs. That's OK,
> but nature is the final arbiter. NT was aware of the electrostatic
> nature of his coils. Much of his work at Colorado Springs was devoted
> to electrostatics. This post may be controversial to some, but I must
> hold my ground. There will be a lot of new work coming out in the next
> few months. As a consequence sparks will be bigger and better in the
> long run. Thanks for your consideration. RWW]
>
> 1/1/96
>
> Bert wrote:
>
> snip
>
> >> If we load the TC with power then decrease secondary capacitance at
> >>the right time then terminal voltage and arcs will increase
> >>dramatically. Perhaps switching a series capacitor in the TC base
> >>circuit in and out at the critical time. Timing in changing
> >>(decreasing) the capacity becomes a feed back challenge that most EEs
> >>should be able to solve.
>
> >>Would this work also by increasing primary capacitance thus
> >>increasing power for a fixed primary voltage?
> >>
> >> RWW
>
> >Richard, Alfred, and all,
>
> snip
>
> >Richard, trying to change Cs "on the fly", although conceptually
> >correct, would be virtually impossible due to the combination of high
> >voltages and rapid switching required.
>
> Actually, voltages at the secondary base are quite low and switching at
> 100-200 kHz is not terribly difficult electronically.
>
Well, this is one EE who doesn't fully agree... although switching 200
kHz is no sweat, switching tens or hundreds of kilovolts at this rate is
far from being trivial. The voltage at the secondary base is low _only_
because we normally tie it to an RF ground. If I understand the proposal
correctly, you'd like to remove the ground and connect a capacitor in
series at the appropriate time (see schematic below) to reduce the
overall capacitance in the secondary system, to further elevate the
output voltage. Lets look at this a little bit more...
I've assumed you want to open up the switch at the critical time when
|Vo| is at the maximum (i.e., when current I = 0) - if this is
incorrect, please let me know. BTW, trying to open up the secondary
circuit when secondary current is not 0 may be even more difficult.
Cs+Ct
Vo ------||------
| |
^ | |
| O | Initial Energy (when I=0):
I | O -----
| O Ls / / / Eo = 0.5(Ct+Cs)Vo^2 Joules
O
O
|
Vx |------
| |
___ 0
Cx ___ / Open Switch when Vo = maximum
| o
| |
|------
|
-----
/ / /
If Cx=0, once we open the switch, the entire secondary and the baselead
rises to Vo.
If Cx>0, the charge originally residing in Cs+Ct will redistribute
across Cs+Ct+Cx. However, since it does so through inductance Ls, it can
be shown that Vx actually oscillates at a voltage that can approach a
peak as high as 2*Vo when Cx << Cs + Ct. However, the TC output voltage
never rises above its initial value of Vo irrespective of Cx. Voltage
multiplication does occur, but at the wrong end of the coil! This is why
the baselead of an ungrounded or poorly grounded energized secondary
WILL find a ground one way or another - it's got the whole voltage
output of the coil behind it if necessary!
> >Fortunately we don't need to do this - there are easier ways! Merely
> >increasing primary capacitance, gap breakdown voltage, reducing
> >secondary capacitance, or improving transfer efficiency will all
> >increase output voltage, as long as the overall system is retuned
> >appropriately.
>
> snip
>
> >Note that, as Alfred suggests, exactly HOW we transfer this energy
> >does not really matter! A Tesla coil simply does it
> >electromagnetically.
>
> Alfred suggests nothing of the kind. Please reread what he wrote.
> Your last last statement is also incorrect. The TC is an electrical
> hybrid. It translates EM energy into electrostatic energy. Your above
> suggestions are all based on electromagnetic concepts. They are valid,
> but we have about pushed the TC EM envelope about as far as possible.
> Alfred, in turn, suggests an electrostatic enhancement of TC terminal
> potential.
I did re-read it, and have reproduced it below. Alfred states that, if
we apply conservation of energy and assume that the energy we had in the
primary is transfered to the secondary, we'll achieve voltage
multiplication by virtue of the difference in capacitances. He also
gives examples of this principle across a variety of pure electrostatic
machines. Conservation of energy still holds for electrostatic,
electrodynamic, or hybrid processes.
Now, while the fundamental voltage multiplication process is the same,
the energy transfer mechanism for the TC is definately NOT the same as
for the VDG, Whimshurst, or other influence machines. If you believe
Alfred is stating that the same electrostatic energy TRANSFER mechanisms
are at work for these AND for TC's, then I misinterpreted his post...
and I'd strongly disagree.
Alfred, could you please shed some light on this?
In the last statement, I indicated that the _means_ of energy transfer
is through inductive (electromagnetic) coupling in the case of TC's. The
only way that the electrostatic energy originally stored within the
primary cap gets transferred to the secondary LC system is via the
oscillating _electromagnetic_ field which couples the primary to the
secondary. Once this transfer is completed, all of the system's energy
resides in the oscillating voltage and current in the secondary/toroid
LC. The output voltage will be increased by a factor of SQRT(Cp/(Cs+Ct))
less transfer losses. The SUM of the electromagnetic and electrostatic
energy in the secondary, assuming no loss, will be a constant. At the
maximum voltage point, ALL the energy resides in the electrostatic
fields of Cs + Ct; 1/4 cycle later ALL the energy now resides in the
magnetic field surrounding Ls.
What part of this is wrong? Are you proposing that the actual TRANSFER
of energy from primary to secondary is electrostatic in nature??
BTW, here's Alfred's earlier post:
=======================================================================
Richard, your observation closely parallels my own work! About
20 years ago I started working on a "Universal theory of
electrostatic magnification" The general principle is that ALL
electrostatic magnifiers; electro-phoresis, Wimshurst machines,
varley machines, the Van De Graph generator and even the Tesla
Coil work fundimentaly the same! Namely through a variance in
capacitance. Everyone with any exposure to electronics is familiar
with the relationship of P = 1/2 C V^2 . If you take a
electro-phoresis you start out with the two metal plates in close
proximity and after charging you pull the plates apart before
dischargeing and in so doing you have DECREASED the capacitance
between the plates and since the amount of energy stored is still
the same, the voltage must go up! The same effect exists in every
electrostatic machine ever devised! In the Tesla coil you have a
large capacitor in the primary and a smaller (distributed)
capacitance in the secondary but since the amount of energy in the
primary and secondary are the same the voltage goes up because of
the difference in capacitance! I have found that the measured
output of sharply tuned resonating Tesla Coils measured with an
electrostatic volt meter correlates very closely to the ratio
of primary to secondary capacitance! Given by:
[Primary Capacitance * (Primary Voltage^2)] =
[Secondary Capacitance * (Secondary Voltage^2)]
Sincerely
Alfred A. Skrocki
alfred.skrocki-at-juno-dot-com
======================================================================
>
> Recent experimentation by RH leaves no doubt that TCs produce large
> amounts of electrostatic potential and are capable of charging distant
> objects with electrostatic energy. These TC experiments are
> reproducible by anyone on this list. I have personally observed these
> experiments.
No disagreement here whatsoever. At the top of the coil there are
humongous electrostatic, potential, ionization, and lord knows what
other effects at work, some of which are still quite mysterious!
However, the mechanism of HOW these voltages are generated is not at all
mysterious, and is fully within the realm of classical electrodynamics.
Electrostatic effects certainly are showing up in combination with ionic
phenomena around the coil.
>
> snip
>
> > Trying to maximize output voltage is not the whole story.
>
> No, but a major part of the story is maximizing TC electrostatic
> potential. There is a major difference between TC EM output voltage
> and electrostatic voltage. They are two distinct types of electricity.
> They use different units. They may exist separately or both together
> in the same circuit. They do not mix or interfere with each other.
> They do not superpose or phase cancel. They are only related through
> basic charge.
I agree fully with all of the above. Where we may differ is in the role
played by electrostatics in the energy transfer process in the TC..
> They may only be interconverted by a "translator". TCs
> are excellent examples of translators.
> High TC terminal electrostatic potential paves the way for big sparks.
>
> RWW
I don't understand this part. Since the base of the secondary coil is
grounded, the purely electrostatic contribution to the TC terminal's
potential is _zero_. Zilch. The mode of primary-secondary energy
transfer is not electrostatic in nature. The peak voltage is coincident
with ALL of the coil's energy being stored in the electostatic field
surrrounding the coil. All LC resonant circuits translate energy back
and forth between electromagnetic and electrostatic components - is this
the EM-ES translation you're referring to? If so, I agree, and there's
really no fundamental differences in our perspectives (other than
perhaps semantic?). If this is NOT what you meant, then I really don't
understand what you mean by the TC being a translator... :^)
Safe coilin' to you, Richard, and Happy New Year!
-- Bert --