More Adjustable Cap Details

From:  Thomas McGahee [SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent:  Saturday, January 24, 1998 12:34 PM
To:  Tesla List
Cc:  Rene-at-compuserve-dot-com
Subject:  More Adjustable Cap Details

> ----------
> From:  Rene Caldera [SMTP:Rene-at-compuserve-dot-com]
> Sent:  Friday, January 23, 1998 12:31 AM
> To:  INTERNET:tesla-at-pupman-dot-com
> Subject:  Adjustable Cap Details
> Tom,
> You had to go and make it very simple, didn't you. :-)
> I was planning on having  a large plastic bolt to move one side in and out.
> Adjusted with a very looong pvc    "nut driver". This way I can adjust with
> the power on.
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> If I make the value big enough then I can adjust down from there just by
> pulling the plates farther apart.
> Rene

Yeah, I like simple things. On your drawing above, I assume that you
drew it rotated -90 degrees and that it is oil-filled to at least
1" above the stationary plates when the moveable plates are in their
full-up position.

May I suggest some improvements? First, I make the assumption
that you are providing some sort of means to prevent the moveable
plates from twisting so as to become non-parallel to the fixed
plates. Easily done with a pair of guide dowels, one on each side,
or by some other means left up to the ingenuity of the builder.
But Keep It Simple! 

All plates must be rigid and parallel. I would recommend sheets of
1/16" plexiglass separating all plates. The plexiglass must be secured
in such a way that it remains immoveable. It should be the same width
as the fixed plate it is mounted against, but rising 1" ABOVE it. You
do NOT want arcs across the top! The reason for using plexiglass
instead of poly is that poly swells in oil. Yes, I know that this means
the variable cap will thus experience more heating and be less
efficient, but you don't want a piece of poly in there expanding away.
The variable cap is to be placed in parallel with a regular cap
anyhow, and so will only be handling a small percentage of the total
system energy. The moveable metal plates should be smaller than the 
fixed plates, with at least a 1" margin along the sides AND bottom
when the moveable plates are lowered all the way.

Now, as to the method of adjustment, that needs some simplifying.
While the idea of using a big plastic screw is appealing, just where
do you plan to find such a beast? A machine shop could make one up
for you, but the price might be a bit much.

The moveable plates are going to be fairly heavy due to the need for
having RIGID plates. Now let that mass and Mr. Gravity come to our
aid. We will let gravity pull the moveable assembly DOWN. Now all
we have to do is come up with a way of getting it UP. I would envision
something that would work almost the same as the mechanism used on
old-fashioned wells to raise and lower the bucket. The shaft can be
(you guessed it) 1" diameter PVC pipe. For the "rope" use heavy duty
monofilament line like that used for catching BIG fish. The larger 
the radial length of the handle, the finer the control you would
have over the moveable plates. Yep, you can extend the shaft out
far enough that the entrepid types could adjust it while the coil
was operating. Just make sure the container is never in danger of
tipping over.

Hope this helps.
Fr. Tom McGahee