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Re: gaps'n'caps

Tesla List wrote:
> 
> >From des-at-ellijay-dot-comFri Oct  4 22:07:02 1996
> Date: Fri, 04 Oct 1996 08:27:13 -0400
> From: Doug Swanson <des-at-ellijay-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: gaps'n'caps
> 
> Just a thought here...
> 
> In using a rotary gap, in moving the rotating electrodes past and away
> from the stationary electrodes, quench ought to be acheived when enough
> distance has separated the points.  I'm considering construction using
> the same RPM motor as has shown good results, using the same number of
> rotating electrodes, but by using simple geometry to come to this
> conclusion, increase the diameter of the wheel that these parts are
> integral to, in order to move each orbiting electrode a greater distance
> per number of degrees that the motor has turned.  This should give me
> less contact time, and a quicker quench as the electrodes move farther
> in their travels (circumference) as the radius increases.
> 
> Also it seems that a larger disk should be steadier in its motion,
> considering gyroscopic effects.
> 
> Any thoughts on this?


Yes.  Larger disks have the disadvantage of high moments of intertia 
(more mass and, often, higher RPMs) and require very precise machine work 
and much heavier motors.  There are always trade-offs!

Richard Hull, TCBOR


> 
> Also, I've considered using a porous (absorbent) material between cap
> foils, which when it soaks up the dial-x oil should provide adequate
> insulation (dielectric) between layers.  (thinking: if a pinhole in the
> polyethylene {original cap design} were filled with the oil, would it
> not maintain the integrity of the capacitor?)  Unless I'm overlooking
> something brutally obvious, it seems that something like cotton fabric,
> which by its nature is full of holes, could even be used as long as the
> oil completely soaked into it.



Try kraft paper or the like.  High energy, high frequency, snubber caps 
often use polypropylene/paper construction, and are pretty good for Tesla 
service.
Richard Hull, TCBOR


> 
> This may be a "ridiculable" idea, (as was the hand-held calculator, 30
> years ago), and I am open to ridicule and suggestions as to whether or
> not this line of thought bears further investigation.  I can see a
> number of advantages to working with a fabric, over polyethylene...

So do a lot of high cap manufacturuers manufacturing snubber caps.

Richard Hull, TCBOR
> 
> doug