Re: Remote Tuned Primary (RTP) ideas...

At 09:31 PM 10/26/99 -0600, you wrote:
>Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>


>The second part is more interesting.  Having thought of many "great ideas"
>and having them all disintegrate for various reasons, I have settled on the
>following:  I will have an "extra" MMC with four stings.  They will have a
>value of 0.5, 1.0, 2.0, and 4.0nF (could be other values too).  This device
>will be parallel with the regular primary cap.  By selecting the strings in
>a binary fashion, I can select from 0nF to 7.5nF of additional capacitance
>in 0.5nF steps.  Four fiber optic cables and simple circuits, as above,
>will select the capacitance from a simple binary thumb wheel switch.  Piece
>of cake!  Except for the four actual switching devices.  

Hello Terry

My first poly plate cap was built like this. I built 4 stacked cap sections
of approx 1,2,4,8 nF in a rectangular glass fishtank. Unlike your design, I
wasn't able to vary the capacitance while the coil was running. Each cap
section had two brass block terminals (for cost reasons) with two 5mm holes
in each terminal. I ran 4AWG single strand copper between the cap sections
and press fitted it into the brass terminals. Connecting different cap
sections allowed me to vary the capacitance between approx 1nF and 15nF. 

Unfortunately, I underestimated the amount of poly I would need to keep the
cap alive and I burnt out the 4nF and 2nF sections while experimenting with
my first coil. Because I am now using Maxwell pulse caps, I haven't
bothered to redesign and repair my plate cap.

For high voltage relays, talk to "Niko Cimbur" <niko-at-fix-dot-net>. He has a
large quantity of ex-govt vacuum actuated relays (Jennings?) from
radio/radar equipment (aerial selectors?). If you email him, he will advise
you on pricing/availability. From memory, I believe he also sells Maxwell
caps and other surplus high voltage equipment. His zip code is 93405-1610

I hope this is of interest,

Gavin Hubbard