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

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 13 Oct 2003 10:19:27 -0600
From: Gomez <gomez@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Re-entrant portion of the sphere (VDG) (fwd)

On Monday, October 13, 2003, at 06:20  AM, High Voltage list wrote:

> Original poster: Steven Roys <sroys@xxxxxxxx>
>
> ---------- Forwarded message ----------
> Date: Mon, 13 Oct 2003 06:55:12 EDT
> From: Lyonelb@xxxxxxx
> To: hvlist@xxxxxxxxxx
> Subject: Re-entrant portion of the sphere (VDG)
>
>   A large diameter sphere with a small re-entrant radius is a must.The
> point
> of column entry is the electrically weakest region on the terminal.
> This can
> be offset to a considerable extent by arranging the electrode with a
> re-entrant portion into which the column fits. This results in a
> diminution of the
> field intensity at this point and thus in a shielding of this
> electrically weak
> region.
>   However  to make this re-entrant  portion is not easy.   Any idea ?

  If you're willing to spend $$$, find a spinning shop that already has
forms for toroids.  A-1 Spinning in Denver has a toroid form for 24"
toroids, and a sphere form for 24" spheres.  All you need is one of
each.  :)  Unfortunately, when you only want one set, the cost is
astronomical, dropping rapidly the more you have made at one time.

  When I built a Van de Graaff in grade school (Science Fair), I
improvised a reentrant sphere using
a "bundt" style cake pan.