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*To*: tesla-at-pupman-dot-com*Subject*: Re: Sphere/Toroid Comparison Chart*From*: "Tesla list" <tesla-at-pupman-dot-com>*Date*: Thu, 10 May 2001 05:51:12 -0600*Resent-Date*: Thu, 10 May 2001 06:12:39 -0600*Resent-From*: tesla-at-pupman-dot-com*Resent-Message-ID*: <YLqm9D.A.feH.zWo-6-at-poodle>*Resent-Sender*: tesla-request-at-pupman-dot-com

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz> Hi Luc, On 9 May 01, at 20:51, Tesla list wrote: > Original poster: "Luc by way of Terry Fritz <twftesla-at-uswest-dot-net>" > <ludev-at-videotron.ca> > > Hi Matt, Kurt, all > > Tx guy, both of your answer are logical, I know that > electrostatic equations are not particularly easy .... To have a > final word on that we probably need measurement and if Matt > theory is good; measurement at high voltage ( not sure about that but > I think the repulsive force could be higher at higher voltage pushing > the charge farther on the exterior ???). > > Cheers, > > Luc Benard I would have thought it was about e.s. field rather than charge distribution?? Suppose you have a toroid charged to some voltage. You can't argue that charges are unevenly distributed over its surface as there would be a potential difference between portions of a conductor and hence a current flow without any input of energy. Y-N? The portions of the toroid facing each other will have a minimal nett electric field between them. Or is my inderstanding incomplete? Malcolm > P.S. I need to try to understand the electrostatic equations ;-) > > Tesla list wrote: > > > > Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" > <Mddeming-at-aol-dot-com> > > > > In a message dated 5/8/01 8:17:07 PM Eastern Daylight Time, > > tesla-at-pupman-dot-com writes: > > > > > > > > Original poster: "Luc by way of Terry Fritz <twftesla-at-uswest-dot-net>" > > > < ludev-at-videotron.ca> > > > > > > Hi guy > > > > > > I post again the same question: If you look at the chart you'll > > > see that until you hit 18" of exterior diameter the toroid with a > > > thickness of 4" have more capacity than one of 6" thickness. > > > Please could some of you explain to me how a toroid with an area > > > bigger could have a smaller capacity. I already know that the > > > surface facing the center ( the hole of the donut ) don't > > > participated as far as the exterior. But the exterior of a 6" > > > thick toroid is bigger than the area of a 4" one. > > > > > > Tx > > > > Hi Luc, All! > > > > I was wrong about the C-C diameter. It is actually the > > exterior > > diameter. I believe the mystery of the smaller toroid can be > > explained like this: For a given major diameter, the toroid with the > > larger chord will have a smaller inner diameter, meaning the > > curvature around the donut hole is tighter. For the smaller inner > > diameter of the toroid with the larger chord, there is greater > > repulsive force between the charges on the inside curve which > > reduces the effective capacitance until that inner diameter becomes > > large enough that the effect is negligible. The smaller the inner > > diam., the more distorted the charge distribution. A 14" outer > > diameter toroid with a 4" chord (6" id) actually has more of its > > surface at a greater distance from the center than one with a 6" > > chord and 14" outer diameter (2" id). The formula, as an > > approximation, also allows for negative inner diameters to be > > computed, which is of course, silly. Matt D. > > > > > Original poster: "Kurt Schraner by way of Terry Fritz > <twftesla-at-uswest-dot-net>" <k.schraner-at-datacomm.ch> > > > > Hi Luc, Bart, > > > > ...you are right Luc, of course! - I did an E-Tesla6 calculation for > > a small coil (2"/10" secondary), supposing a 12"/4" vs. a 12"/6" > > toroid, and got: > > > > Problem: Medhurst E-Tesla6 Diff=~ > > d1 d2 C.bert.P. C.sec. C.total C.toro Fres > > (inches) pF pF pF pF kHz > > 12" 4" 13.262 4.153 15.116 10.963 522.27 > > 12" 6" 11.585 4.153 16.350 12.197 502.17 > > > > Up to now, I was very close to the measurements on my coils, with > > Bert Pools equation. But those were not in the same range of toroid > > data. So, reading your first poster, was not recognized well enough > > (by me). I guess, we are just outside of the validity limits for the > > (probably-; if Bert is reading, he might comment!) semi-empirical > > Bert Pool's equation. This equation may well be continued to use in > > "normal" TC-design procedures, but when it comes to somehow extreme > > toroids or toroid vs. secondary situations, not be the method of > > choice. The real things are something like the super-cool > > measurements of Bart Anderson, which obviously support the use of > > E-Tesla6. More of this kind of measurements, together with the > > outcome of the TSSP, will probably lead to design procedures, which > > are more precise, but, perhaps, more important: applicable to a > > broader range of TC-parameters. > > > > Cheers > > Kurt Schraner > > > >

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