Re: Capacitor and coil form questions-Tesla (fwd)

---------- Forwarded message ----------
Date: Wed, 14 Jan 1998 21:58:14 -0500
From: bmack <bmack-at-frontiernet-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Capacitor and coil form questions-Tesla 

Tesla patented a capacitor much like the "fish tank" cap except the sides
had grooves to maintain the spacing of the rigid plates.
I think I'll try making onre myself. The flexibility of adding and removing
is very attractive not to mention the repairabilty factor.

Jim McVey

> >>>>"
>         Take an 8"x8"x12" glass fish tank, cut metals plates so that they
> suspended on the ledges at the top of the tank, and have a connecting
> bolt running down each side connecting alternate plates. Fill the tank
> with transformer oil. I have calculated that 85 plates, 2.5mm appart
> should give he the desired capacitance.
>         I think that this design has several advantages, the di-electric
> self healing, and it is easy to adjust capacitance and voltage.. For me
> these outway the difficulty of moving and setting up the capacitor"
> <<<<
> 	That's mighty close spacing!!!  You would need very flat
> plates, rigidly supported.  In my opinion that would be nearly
> impossible to achieve in practice.
> 	As for the self healing - not so simple.  I have a couple of
> variable capacitors immersed in oil here.  When breakdown occurs the
> oil is carbonized, and think a complete emptying of oil, flushing and
> washing plates in solvent, and refilling would be needed.  
> 	There was an article in QST sometime around 1921 describing
> a 375 meter (800 kHz) spark transmitter using jus such a capacitor.
> The builder/designer seemed to think it worked fine.  (Those guyhs
> guys knew their stuff back then!)
> Ed