From: Paul
Date: Fri, 18 Oct 2002 11:54:52 +0100
Subject: Re: [TSSP] Top Voltage
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.