TSSP: List Archives

From: Bert Hickman
Date: Fri, 18 Oct 2002 07:20:31 -0500
Subject: Re: [TSSP] Top Voltage

Paul,

You're correct. In the sphere-sphere case, V should be defined as the 
differential voltage between the spheres. This is also the case in the 
sphere-plane case as well, but the plane is often set to ground 
potential. So, Figure 7.4 is inconsistent with the corresponding 
gradient equation - the battery voltages should indeed be +/- V/2 
instead of +/-V.

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
"Electromagically" (TM) Shrunken Coins!
http://www.teslamania.com

Paul wrote:
> Hi All,
> 
> Further to last message, I'm definately an idiot, but
> unfortunately the model is correct after all.  There was
> a typo in my test setup involving the North report formula.
> 
> Having fixed that, the model agrees with North again. 
> The error on max surface field is circa 0.5% for a sphere well
> above the groundplane, and deteriorates as the sphere becomes
> lower, reaching 5% error when the sphere-plane gap equals the
> sphere radius.
> 
> Oh well.  
> 
> I think there's something wrong with fig 7-4 on p59.  
> The formulas for sphere-sphere peak gradient only make
> sense if the spheres in fig 7-4 are at +/-V/2 rather
> than +/-V.   In other words, the formulas seem to be
> correct if V is taken as the differential voltage between
> the spheres, rather than the voltage between either sphere
> and a zero of potential at infinity.  Can someone check this
> conclusion?
> 
> --
> Paul Nicholson,
> --
> 






Maintainer Paul Nicholson, paul@abelian.demon.co.uk.