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Re: Isotropic Capacity
Subject: Re: Isotropic Capacity
Date: Mon, 26 May 1997 13:47:40 -0400 (EDT)
From: richard hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
snip
> A coiler would be interested in the exact capacitance value of the
>toroid
>when on the top of the secondary coil because with the secondary coil
>inductance it determines the operating frequency of the TC.
>
>The capacitance of the sphere is higher when isolated in space than when
>on
>the TC secondary coil. Do any coilers know why?
>
> John Couture
>
>
I have always found that any isolated capacitance when considered as a
capacitive device and connected to or near enough to another capacitive
isolated device forms a simple series capacitive circuit.( with
reference to
gorund) This makes the large device appear to possess less than its
full
isotropic capacitance with reference to ground, which is where we always
reference most isolated isotropic capacitive measurements on earth.
These series circuits are subtle and complex in multibody problems
especially when close to the earth with relation to the sizes of the
bodies
under study. This is why the theoretical equations are just no good for
the
realized values of "inuse" isolated capacities for Tesla coils. (Always
give
results which are too high compared to values derived from measurment.)
The largest capacitance possible on earth for any isolated conductive
body
can only be reached when 10X its major axis from the earth. Otherwise
it
would be required to be at "capacitor plate" distances (<<<10 x major
axis)
from ground to rise above that value.
Richard Hull, TCBOR