Re: Proposed capacitive transformer TC?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: "Jolyon Vater Cox by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
> 
> Here is the schematic in the correct font (Courier New)
> -I hope it comes out correctly this time!
> 
>                                 (=+=)
>                                   |
>                                   L2
>                                   L2
> ---------+------L1------+-----)   L2   (  EIP1
           |              |         L2
> PSU     SG1             C1        L2
>          |              |         |
> ---------+--------------+---------+----GND

Still misaligned. I corrected the alignment. Can you see it?
"|" makes a better vertical line than "I".

> Description:
> The electric induction plane EIP1 is a metal plate with
> hole in the middle wide enough for L2 to stand within the
> enclosed space without touching; it is
> connected to L1, C1 and SG1 the spark gap, it  not
> connected to L2 the secondary coil other than by
> capacitive coupling.
> L2 is grounded at one end and connected to a toroid at
> the other.

I built a more elaborated version:
http://www.coe.ufrj.br/~acmq/tesla/mres4hp.jpg
L1 is the large red inductor. C1 is the tube at its right side.
The NST is missing in the picture, and also an insulator below L1. 
I made a wood disk with a large hole and glued a strip of aluminum
foil over it, interrupted to not form a loop. It is insulated
from the ground with three glass pots.
A low-power test shows that it works in mode 20-21. Vc1
shows 10.5 cycles before the first notch:
http://www.coe.ufrj.br/~acmq/tesla/mres4hp1.jpg
Faster modes are possible by rising the induction plane,
but eventually it would work as a strike rail.
I didn't test it at high power yet, but it will surely work, if
sparks don't appear between L2 and the ring, and the aluminum
foil supports the current.

I am really liking the antenna at the terminal for tuning. Much 
easier than changing L1, and allows very fine tuning.

> An interesting feature is that it is an
> "indirectly-coupled" system. Also it seems to me that
> if EIP1 were driven by RF generator the system would
> essentially become a Magnifier but with the RF connection
> to the bottom of extra coil and the ground plane
> interchanged ie.L2 the "extra" is directly connected to
> ground and RF is applied to the plane -the opposite to
> the usual Magnifier configuration.

You are right. A magnifier version is surely possible, but too
much voltage at the induction ring would require a different
construction. A smooth toroid with a large hole, for example.
 
> The same would result with the spark-gap excited circuit
> if the positions of L1 and C1 were interchanged.

Really, in the schematic above, L1 and C1 can be interchanged. 
The connection is then safer. With C1 grounded the NST is 
directly connected to the induction plane.
 
> Is this reasoning correct-only it seems to me that in a Magnifier the
> question of whether or not HV RF was supplied to the base of the extra coil
> with the planar electrode grounded OR the the base of the extra coil was
> grounded and HV RF to supplied the planar electrode would not matter much,
> electrically speaking.

Surely. A problem with these capacitively coupled structures is that
the grounded final resonator has capacitance to the ground too.
Without some form of compensation, this reduces the effective
coupling, and forces operation at a slower mode.

Antonio Carlos M. de Queiroz