Re: Re-entrant portion of the sphere (VDG) (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 14 Oct 2003 07:00:36 EDT
From: Lyonelb@xxxxxxx
To: hvlist@xxxxxxxxxx
Subject: Re: Re-entrant portion of the sphere (VDG) (fwd)


Dans un courrier daté du 14/10/03 5:39:12, hvlist@xxxxxxxxxx a écrit :

<<Use a torus instead of a sphere?>>
Thanks for your answers.

  Franklin B. Lee said ' The opening which admits the belt to the collector
ought not to be much larger than half the diameter of the collector and should
be smoothly curved inward, using a generous radius of curvature. Unpolished
commercial aluminium spinning, free of lint and dust, will collect about 85 per
cent of the theorical maximum.A high polish will increase the voltage another
1 per cent. The concentration of charge around the hole through which the belt
enters accounts for the remaining 14 per cent, a quantity which varies with
the size of the hole and its distance from other conductors.'

  J.G. Trump gave an excellent example of the correct design of a Van de
Graaff high voltage terminal. Instead of a sphere, the terminal is a flat topped
toroid. Equipotential rings are used on the supporting column ( 500 kV @ 200
microamp. is generated by this 1938 design ). ( cf
www.lateralscience.co.uk/VDG/trump.html).

  OK. But I believed in  homemade stamping/embossing/swaging/pressing tech.

Lyonel Baum