From: Paul
Date: Fri, 20 Oct 2000 00:45:35 +0100
Subject: [TSSP] Progress report 18th Oct 2000
A quick note to summarise the project status, as quite a bit of ground has been covered lately and I just wanted to paint a clear picture of where we're at. Theory notes pn1310 at http://www.abelian.demon.co.uk/pn1310.ps section 5 onwards contain simple, physically justifiable extensions to transmission line theory in order to accomodate the longitudinal couplings of a tesla coil. These extensions are self consistent and converge, in the absence of longitudinal coupling, to the standard transmission line solutions. The theory forms the basis for this project's tsim simulator which is known to do a reasonable job of predicting resonant frequencies and the dispersion due to the longitudinal coupling. A number of other testable predictions emerge: A) Expected V/I profiles are described in pn1710 at http://www.abelian.demon.co.uk/pn1710 and some of these examples could and should be checked by experiment. B) Also pn1310 equations 7.7 and 8.4 place approximate bounds on the resonant frequency when Cmed is either calculated from the geometry by a laplace solver, or measured for the coil in-situ by the 'Medhurst/Howe' method. This could be confirmed by reference to already published measurements, and by new measurements. C) Further, predictions of transimpedance, equations 9.1 and 9.2, can be put to the test by simultaneous CW measurements of base current and top voltage. Finally, there are a number of interesting consequences of the basic theory pn1310, which may be hinted at in some of the examples in pn1710. These may possibly have some bearing on efficient tesla coil operation. Obviously these would be contingent on satisfactory experimental confirmation of the points listed above. It has become clear that some considerable attention needs to be paid to finding ways to produce reliable unequivocal voltage profile measurements. Existing methods are producing conflicting answers. Here's hoping the experimenters out there will rise to this stiff challenge. Just few general points about theory notes and things. I've posted up a few items lately but not had much feedback from the list apart from Terry. Not having any other review process available I'm completely dependant on the list members to scrutinize project material and challenge anything that's at odds. We've seen recent examples where faulty ideas have gone unchallenged by critical review and thus worked their way into the common understanding. I'm sure we're all anxious not to contribute to this and our only safeguard is the willingness to criticize one another's efforts. Only then can we claim to be engaged in a scientific process. I also believe that if someone presents an idea, the onus is on them to be able to fully explain it properly, so if I've failed to do that anywhere, please do point it out. Some recent discussions turned to the subject of primary operation spark gaps, and arc/corona loading. Boris wrote: > Hmm..Seems we are digressing bit of concentration to > bare secondary behavior (without arcs).OK,I can live > with that. I can live with that too. Although this list was set up to carry discussions relating to a particular software project, I've no desire at all to enforce that. Personally I'm quite happy to see posts on other technical issues. Recent discussions on primary gaps and secondary arc loading have certainly sparked my interest. In terms of scope, I see the following topics as being particularly relevant to tesla coiling state-of-the-art: * Primary gap characteristics and their bearing on efficiency. * Primary/secondary coupling, optimisation for minimum transfer time. * Dependency of secondary V/I distributions on the system geometry. * Optimisation of geometry to achieve the most favourable V distribution for a given stored energy. * Effects of corona and arc loading on secondary operation. Currently only the 3rd and maybe the 4th item are within the scope of the tsim/tlap modeling program but I don't see any need to constrain the project to those. On the contrary, I think we'd all agree that the secondary can only be understood properly in context, so I propose that the list of topics above be taken as a guide to scope. I think we have between us the ingredients to make some real progress on these topics, and I for one am feeling quite excited about the prospects. That's all for now, Best regards to all, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.