Antonio - variable vacuum capacitor if you want

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Antonio,

I tried mailing you direct, but it bounced...

I was looking over your coil at:

http://www.coe.ufrj.br/~acmq/tesla/mres6.html

And noted you were having trouble with C2.  Would a capacitor like this:

http://hot-streamer-dot-com/temp/Pc260028.jpg

Be of use to you?  It is a variable vacuum capacitor made by Jennings

CSVF-500-0315
15kV
12-500pF

http://www.jenningstech-dot-com/pdf/cap/vacvar/csvf500.pdf

http://www.jenningstech-dot-com/technotes/technotes.shtml

They take 15kV peak, 100 amps (but that is continuous RMS heating,  1000's 
of "real" amps ;-))), 12- 500pF at the turn of the screw knob (turn the 
power off first ;-)), and they have practically no loss.

This is just an old one I have laying around and have no use for.  It's 
free and I'll shipping to you free to Brazil if you want it.  Let me know 
if you can use it and the address to send it to.

I am very interested in your new transformerless coils ;-))

Cheers,

         Terry
         terrellf-at-qwest-dot-net


At 10:14 PM 12/11/2002 -0200, you wrote:
>Tesla list wrote:
> >
> > Original poster: "J. B. Weazle McCreath by way of Terry Fritz 
> <twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>
> >
> > During a period of insomnia overnight I was musing about the need for
> > tight compling, or high K value, in the driver portion of a magnifier
> > type T.C.  Has anyone ever tried a bifilar winding arrangement for a
> > means of achieving this?  My thought was to pull a heavily insulated
> > lead through a length of 3/8" copper tubing before winding a solenoid
> > type primary.  You would need to either employ an off-axis inductor
> > or a variable tank cap to tune, but it sure would yield a high K for
> > the driver portion.  Ideas?  Comments?
>
>This looks as using a coaxial cable to wind the transformer. If the
>system doesn't require too high voltages between primary and
>secondary, looks ok. You really can use an off-axis inductor for
>tuning the coupling. A too high coupling is not necessary. The
>fastest possible energy transfer is obtained with k=0.67.
>
>Some observations about magnifiers:
>
>A magnifier is different from a regular Tesla coil only if a
>capacitance is added across the secondary coil. This increases a lot
>the speed of the energy transfer, and makes all the difference. See:
>http://www.coe.ufrj.br/~acmq/tesla/magnifier.html
>
>It's possible to eliminate the transformer, if a grounded power
>supply is used:
>http://www.coe.ufrj.br/~acmq/tesla/mres6.html
>
>A magnifier with fast energy transfer is highly insensitive to
>precise tuning. If the energy transfer takes many cycles, the
>sensitivity to the tuning increases.
>
>A magnifier generates long notches in the primary waveforms, what is
>better for first notch quenching. In a conventional Tesla coil, the
>beats in the primary waveforms follow the absolute value of a cosine.
>In a magnifier, they follow approximately a squared cosine.
>
>Antonio Carlos M. de Queiroz