From: Paul
Date: Fri, 08 Dec 2000 14:22:22 +0000
Subject: Re: [TSSP] E-Tesla6.11
Terry wrote: > I tried to avoid "fudge"factors but was always ready to use them with > wild abandon if needed ;-)) We really needed a program that simply > "worked" no matter what the method. Agreed, unlike tsim which isn't allowed to have *any* fiddle factors - if tsim gives the wrong answer then either the physics or the code is faulty. > It was only a two years ago when such things we deemed > impossible by many and now it seems like we have been doing such > calculations for 50 years without a second thought ;-)) Worrying really, since we're not doing anything fundamentally new in this project - its just a thorough application of transmission line theory, only a little more sophisticated than the standard analysis of the uniform line as taught to undergrads. Beats me why nobody has put this together before now. Maybe they have but I've not been able to find it. I suspect the academic community shies away from things tesla related due to the pseudoscience that the subject has collected over the years. > It is a little scarry that your project showed such a dramatic error > in the secondary profile in the 5 version of the program but > reassuring that the results were simply made even more accurate when > the error was corrected. Just goes to show that those fiddle factors can successfully hide some big gaps in the physics. And if the answers didn't improve when the factors were replaced, then that would suggest that compensating errors are at work. In this case I think that the '5 profiles were covering the lack of an appropriate effective inductance. Now of course, you're still having to cover that gap with an Lfac, but at least the Lfac has a well defined purpose and promises to be calculable in the not too distant future. > E-Tesla has gone through a lot of twists and turns so it should be > on the right track as far as methodology goes. A few more to come, no doubt, but certainly on the right track. It's the only program I could recommend to a coiler. > It has been 100 years now and not knowing the secondary voltage > profile and other basic things has always struck me as ridiculous. > We put a man on the moon over 30 years ago so we should be able to > figure out the voltage of a large aluminum toroid 5 feet in front of > us now... Yes, I encountered exactly this feeling when I sat down to design a big CW coil. Not being able to cover the expense of trial and error I began a thorough design but was immediately thwarted by the secondary formulae - amazingly there weren't any - anywhere, except a few that were obviously wrong or naive. I could find nothing with which to calculate the Fres, input impedance, Q factor, and top voltage - all of which are basic to any design. Thus began this project. > One little aspect "I" really will enjoy about the secondary profile > thing, is that it was accurately predicted by computer modeling > BEFORE that profile was demonstrated by measurement! Yes, nice that. What I like best is that the dv/dx profile also matched very well, implying that the predicted current profiles are valid. In particular the max current point being some way above the coil base, that really surprised me when it came out of the simulator - hence the need for your unequivocal measurements to prove that it wasn't just an artifact. I must say that I was delighted that your V accuracy was adequate to confirm this phenomena quantitatively. > I used to be prodded by the "seat of the pants" coilers who ridiculed > people whose coils were made of electrostatic charges in little > silicon gates made by Intel. So I get a always get a little thrill > now poking them boys back ;-)) Sure, trial and error coiling is fun - and what else can you do without a firm theoretical basis for design. But tradition is a poor substitute for knowledge. > ... So don't screw up! :-))))) A good point that I'd like to make some comments on. Expect another post to follow, Cheers, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.