# Re: [TCML] BIPOLAR TC DESIGNS

On 11/17/15 6:22 PM, Harvey Norris via Tesla wrote:
One of the things about bipolar systems that seems to be neglected is
what  would or could occur if the top load polar capacity of each TC
side were replaced with endings of  a conventional dual plated flat
capacity; essentially establishing a much tighter capacitive coupling
between the systems themselves. For example if we replaced the
surface area of each top load with an equivalent flat surface area
and then brought these plates in closer proximity in space the
conventional two plated capacity would begin to outweigh the effects
of just each polar capacity alone.

So what you are saying is that rather than treating the "top loads" (end loads?) as "capacitance to infinity", if you bring them close enough together, it will look more like a conventional "two plate" capacitor.

I don't think the surface area is particularly relevant other than more area = more capacitance. That is, the self C of a plate of 4pi square meters isn't the same as the self C of a 1 meter radius sphere.

Unfortunately, there's not a nice closed form solution to the capacitance between two spheres (or a sphere and a plane). http://www.electrostatics.org/images/ESA_2014_G_Banerjee_et_al.pdf has a nice discussion..

Let's put some practical numbers on this.

let's say the spheres are 30 cm in diameter, about 17 pF. And they're a meter apart.

If you have a circuit that is basically ground:Ctop:Lsec:Ctop:ground, the two C's are in series, so the net is about 8.5 pF.

what size plates separated by a meter would give you an 8.5 pF capacitor?

C = 8.85pF * A/d

so, your plates need to be about 1 square meter.  That's pretty big.

BTW The 30cm diameter sphere surface area is 0.28 square meter.

Indeed we should be able to move
these plates so close together that the combined circuits would have
too much capacity for the designed high frequency resonance dictated
by L(p)C(p) and the systems would go out of resonance.

Well, yes.

There appears
to be a wide margin between what is obtainable with just polar
capacities alone and that of introducing a dual plated capacitive
coupling between the systems. Supposedly we have equations to deal
with conversions such as this but it seems very incongruous, somewhat
like mixing apples and oranges, both are fruits but they don't seem
comparable in actions. For instance would it even be possible to
eliminate half of the polar capacity and replace the missing half
with a conventional dual plated capacity?

Yes, you could have a 17 pF capacitor to ground (as long as it can stand the voltage).

Would the secondary arcing
activity be diminished? (it would seem to be so).

Not really.. I think that's more about the field distribution around the top load, and a large flat plate will have "edges". Now, a rolled edge might help (or a Rogowski profile), but now you're kind of looking at two big toroids.

A toroid is sort of a flat plate with a large radius of curvature edge. I suspect (without calculating it) that the "free space" capacitance of a toroid, of say, 1 meter diameter, with 30cm diameter tube and 30cm flat plate in the middle is pretty close to something that would have the same 30cm diameter tube in a ring, with flat plates on either side (so the top and bottom don't have an indentation).