Re: Source for Aluminum Spheres (up to 12" threaded)

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

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 >
 >  > Original poster: Ed Phillips <evp-at-pacbell-dot-net>
 >  >
 >  > Tesla list wrote:
 >  >  >
 >  >  > Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com>
 >  >  >
 >  >  >  >      Has anyone here ever compared large spheres with toroids for
 > top
 >  >  >  > loading of high-power TC's?
 >  >  >  >
 >  >  >  > Ed
 >  >  >
 >  >  > Toroids do much better than spheres.  I believe the first person to
 >  >  > start using toroids was back in the 1970's from
 >  >  > what i've read from Richard Hull's historical notes.
 >  >  >
 >  >  > Dan
 >  >
 >  > In what way better?  Clearly they work just fine but wonder what their
 >  > edge is over a sphere with the same breakdown voltage.
 >  >
 >  > Ed
 >
 > One way I can think of is that a toroid gives you mostly independent control
 > over the breakout voltage and topload capacitance.  The major diameter
 > mostly controls the topload capacitance.  The minor diameter mostly controls
 > the breakout voltage.  With a sphere, you don't have this level of control.
 >
 > Gerry R
 > Ft Collins, CO

	OK.  That's the only difference I can think of too.  Of course, a
sphere with a breakout point is another way to go.  I have a kind of
theory here that the more topload capacitance the better (lower resonant
circuit L/C and hence surge impedance) but haven't thought about how to
prove that.  I do know that going to toroidal upper terminals sure
revolutionized "the business"!

Ed