Re: Magnifier topload size?

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

Original poster: "Edward Wingate by way of Terry Fritz <teslalist-at-qwest-dot-net>" <ewing7-at-rochester.rr-dot-com>

Tesla list wrote:

 > Original poster: "Jeff W. Parisse by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <jparisse-at-teslacoil-dot-com>
 >
 > TCML,
 >
 > A smooth metal toroid is the only pro way to go. Bumps or surface
 > perturbations lowers the breakout voltage by leaking off corona (or
 > streamers). A totally smooth toroid will develop the largest charge
 > before breakout and usually makes longer arcs. Many years ago (before
 > the founding of kVA) we compared many "homebuilt" alternatives to the
 > Smooth AL toroid and the results were pretty obvious that the smooth
 > toroids worked "better".
 >
 > Greg's method allowed visitors to climb into the sphere and look out. I
 > bet he'd have more pF with a smooth continuous surface.
 >

Jeff,

When you say "better", did you A/B spark lengths at the same power level?

I wasn't referring to the sphere. I think Greg had a tubing toroid in 
addition to the sphere that was
installed on Electrum in the final installation, but I don't recall what 
the actual dimensions were.

With identical sizes there is some difference in spark output between home 
built and spun toroids,
dependent on the care taken in construction. I have seen copper and 
aluminum covered home built toroids
constructed by Tim Davy in the UK that were as smooth as any spun toroid I 
have ever seen seen.

I was talking about a home built toroid at least twice the size of the spun 
8' or so that seems to be the
practical limit in size for spun aluminum. There WOULD be an increase in 
spark length with a toroid twice
the size, homebuilt or not. How much increase TBD.

The curve of the  toroid tends to better shield any surface imperfections 
in larger sized toroids than in
smaller diameter and cross section toroids.

Ed Wingate RATCB