Re: Alternate toroid shapes

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Original poster: "Brian" <ka1bbg-at-webryders-dot-net> 

I have used fan shrouds with great success. Frying pans put lip to lip work
well also. I manage to get very close to John Freau's length formula after
measuring the input power. cul brian f.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, December 16, 2003 9:48 AM
Subject: Re: Alternate toroid shapes


 > Original poster: robert & june heidlebaugh <rheidlebaugh-at-desertgate-dot-com>
 >
 > I have used Beer Kegs in the past, Ther aluminum and stainless steel kegs
 > have rounded ends not sharp ends like an oil drum. I know that is not the
 > clasical toroid but they hold a charge to 2 mega volts.
 >     Robert   H
 > --
 >
 >
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > Date: Mon, 15 Dec 2003 11:58:49 -0700
 >  > To: tesla-at-pupman-dot-com
 >  > Subject: Re: Alternate toroid shapes
 >  > Resent-From: tesla-at-pupman-dot-com
 >  > Resent-Date: Mon, 15 Dec 2003 12:20:55 -0700
 >  >
 >  > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >  >
 >  > Oops.. hit the mousepad..
 >  > The hemisphere on hemitoroid was advocated by Craggs and Meek as well
(and
 >  > probably Robert Van deGraaff as well), but probably not for any
 >  > electrostatic field reason, but because it was easy/feasible to make.
Some
 >  > of the designs in Craggs and Meek have a somewhat flattened top (rather
than
 >  > a hemisphere), and you see, in the literature, references to "spherical
 >  > electrode with re-entrant curvature where the belts go through"
 >  >
 >  > Some of the "big iron" vdg's (operating in pressure tanks) use a top
 >  > electrode that is basically cylindrical, with a hemispherical top and
the
 >  > hemisphere with a hole with curved edges at the bottom, increasing the
 >  > electrode capacitance (and, making more room for "stuff" inside the
 >  > electrode, like ion guns, charging supplies, etc..
 >  > ----- Original Message -----
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > To: <tesla-at-pupman-dot-com>
 >  > Sent: Sunday, December 14, 2003 5:32 PM
 >  > Subject: Re: Alternate toroid shapes
 >  >
 >  >
 >  >> Original poster: Dave Leddon <dave-at-leddon-dot-com>
 >  >>
 >  >> Back in the sixties I purchased a three foot diameter spun aluminum
oblate
 >  >> from F. B. Lee (anybody remember his contributions to the Amateur
 >  >> Scientist) who claimed that this shape, which resembles a hemisphere
on
 >  > top
 >  >> of a toroid, was the best shape for a Van de Graff generator because
it
 >  >> would accumulate maximum charge while minimizing break down on the
 >  >> supporting column.  I often wondered if this shape would represent any
 >  > sort
 >  >> of improvement over the classical toroid.
 >  >>
 >  >> Dave
 >  >>
 >  >>
 >  >> At 10:53 AM 12/14/03 -0700, you wrote:
 >  >>> Original poster: Paul Nicholson <paul-at-abelian.demon.co.uk>
 >  >>> John Richardson wrote:
 >  >>>
 >  >>>> Has anyone done any experimentation into toroid topload shapes
 >  >>>> other than the typical round designs that all use?
 >  >>>
 >  >>> AFAIK little has been done.
 >  >>>
 >  >>> Toploads have two important parameters:
 >  >>>
 >  >>> a) the amount of charge they hold per unit volt, a.k.a the
 >  >>> capacitance.
 >  >>> b) the voltage at which they begin to issue streamers.
 >  >>>
 >  >>> Toroids tend to have a larger capacitance for a given breakout
 >  >>> voltage, compared with sphere terminals.  And they seem to be
 >  >>> preferred for streamer formation, perhaps because of this.
 >  >>>
 >  >>> But who is to say there isn't a better shape?   It could be
 >  >>> that the best streamer formation comes from toploads with modest
 >  >>> breakout threshold plus large charge storage.
 >  >>>
 >  >>> You could approximate your proposed tear drop cross section with
 >  >>> a sphere or toroid with a disc shaped skirt, so that from a
 >  >>> distance it looks a bit like Saturn.   You would have to tell
 >  >>> us whether it behaves any differently to a toroid plus breakout
 >  >>> point.
 >  >>>
 >  >>> Plenty to do here for theorist and experimenter.  See recent posts
 >  >>> by Antonio for the relevant modelling programs.
 >  >>> --
 >  >>> Paul Nicholson,
 >  >>> Manchester, UK
 >  >>> --
 >  >>
 >  >>
 >  >>
 >  >
 >  >
 >
 >
 >