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

Hi Terry,
    I have designed high voltage relays up to 1 MV for a few dollars
worth of parts, as Ross was not a monetary option in most of my
projects at the lab.  Buy some of the (at least 2") throw pneumatic
cylinders available from one of the hobbiest catalogs for a few
dollars each, or if you prefer, use a washing machine solenoid, etc.
Attach a dielectric rod, with a brass ball attached to the other end,
of the throw rod (usually threaded, just drill and tap a hole).  If
the rod is long, for higher voltages, it may need to be supported.
Fix a brass ball, oposite to the ball on the end of the rod, to a
rigid dielectric post.  When the pneumatic cylinder or solenoid
extends, the brass balls will come into contact, closing the circuit
attached to them.  I prefer the pneumatic cylinder because the contact
pressure and throw rate can be controlled.  The pneumatic cylinder
also has the advantages of unlimited range and safety isolation.  The
same catalog contains pneumatic air switches which can be used to
control the air to the cylinders.  You can control these with relays
which can be interfaced to logic if required for complex timing, etc.
With this method you could design a self tuning coil with ease using
logic control interfaced to a current probe at the base of the
secondary.  Swagelok fittings and polyethylene tubing for the
connections can be found at industrial supply houses or at a good
industrial junk yard.  For total portability a tire inflator makes a
good air cource.  Depending upon the size you may need a reservoir
tank.

    Another way is to pivot the dielectric rod about one end on a
smooth shoulder bolt.  Attach the solenoid or air cylinder close to
the pivot (either side).  When the solenoid or cylinder extends, the
rod will swing with an angle theta around the pivot.  Since s=r*theta
then the other end of the rod can be made to move a much greater
distance (the lever principle).  Mount a ball on this end.  The
contact opening is limited only by the rod length.  I designed a 1 MV
relay this way using 2" PVC pipe for the rod and a long 3/8" bolt for
the pivot.  Pneumatic air cylinders are really nice for this because
they are very powerful and don't heat up.


Barry



----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, October 26, 1999 8:31 PM
Subject: Remote Tuned Primary (RTP) ideas...


> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> Hi All,
>
> One of my new projects (one of a zillion I have planned for the cold
> months ;-)) is to make a remote primary tuning device.  It has two
parts: