Re: Sphere-in-Sphere

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:
 >
 > Original poster: "john cooper" <tesla-at-tesla-coil-dot-com>
 >
 > Hello Antonio, et. al.:
 >
 > When you mentioned "two spheres almost touching to produce longer sparks",
 > I'm trying to picture the electrical connections.  I imagine one sphere
 > would be connected, as normal, to the secondary/extra-coil.  Now the second
 > sphere, I'm thinking that one would be suspended or supported by some
 > non-conductive means?  Maybe suspended with nylon fishing line?  That
 > arrangement would make sense to me.  If they were close enough, maybe an
 > inch or even less apart I would think their fields and therefore their
 > capacitances would combine.  I've got to try that but does that sound like
 > what you were thinking.

Yes, one sphere connected normally, and the other suspended above it, or
besides it, at a small distance. A possibility would be to glue a ring
of
PVC tube on top of the lower sphere and place the upper sphere supported
by it, maybe glued too to avoid disasters. Make some holes in the tube
for ventilation.

 > As far as the sphere-in-sphere is concerned, I'm beginning to believe that
 > arrangement basically takes advantage of the empty space inside the larger
 > sphere to accommodate another which results in their capacitances being
 > added.

No, this would not happen. With the outer sphere floating, it is just an
equipotential surface around the inner sphere, and doesn't affect the
capacitance of the inner sphere, or its breakdown voltage (ignoring
irregularities due to the presence of the coil below). This can be
easily
verified by measuring the resonance frequency of the system, with the
spheres insulated and interconnected. The combination
would start as a small capacitance, but as soon as a spark puts the
spheres in connection the effective load would be the outer sphere
alone.
In another post I said that a possible reason for improved performance
would be the fast variations in the electric field around the outer
sphere due to the sparking between the spheres. The rectification may
have some effect too.

 > Now the twist in this is in Tesla's magnifier diagrams where the
 > second sphere, which is above the first, not inside of it, rectifies the
 > output.  I can usually work out these problems in my mind before I put
 > pencil to paper but I've got some more work to do on this one.

Sparks can have some rectification effect, but that diagram (from
where?)
shows a symmetrical gap, that should not rectify.

Antonio Carlos M. de Queiroz