From: Paul
Date: Wed, 30 May 2001 11:23:24 +0100
Subject: Re: [TSSP] Secondary in motion
Terrell W. Fritz wrote: > What a fascinating movie! Ah, you should see the full feature-length big-screen version! But its many tens of Mbyte - had to trim most of it away to get it down to a reasonable filesize (: > It does look a lot like a steel ruler that is bumped a bit to > get it moving. Quite a wriggly-writhing thing isn't it? Even just 5% of mode 3 gives that character to the motion. With the pure steady state response at f1, we just get the very boring flopping from side-to-side of the familiar profile. > I have a request if it would not be a bother. Could you make > the same thing but with a much higher coupling (like 0.3)? Ahead of you there, already on with it. I raised your primary 10cm and remodeled the coil, ... http://www.abelian.demon.co.uk/tssp/tmp/tplot.14725.out.gif for the charts. I figured your real primary would not go any higher up, so thought I'd better do this one with the virtual! I'll generate a movie of this one and post it up later today (will be after 12:00 your local time - our Telecom charges get a lot less per second in the evenings!) > I am wondering if the racing arc cause may show itself. We often > hear (just today) that raising the secondary (lowering the coupling) > cures racing arcs along the secondary. Perhaps the high coupling > mixed with these higher modes is causing local high voltage areas on > the secondary that promote racing arcs? Well one way or another the voltage gradient is exceeding the turn/turn breakdown limit of the secondary, but whether its simply too much induction from the primary, or whether mode 3 is adding to the problem, remains to be see. But I think we needn't wait too long... Bear in mind that mode 3, if at say 10% amplitude, will place (roughly) an additional 10% of the *topvolts* across the bottom 3rd of the coil. (as opposed to 10% of the normal voltage at 1/3rd height), which helps explain why its so clearly visible in the movie, even at around only 5% mode 3 amplitude. BTW, Rather than plot the voltage profile, I think we'd see a clearer picture if the *gradient* was plotted, ie as in the type of chart in http://www.abelian.demon.co.uk/tssp/pn2510/ so that we can just read off the volts/turn and see clearly whereabouts on the coil it peaks. I'll try to make time today to run a couple of these through the movie-making script. I'll also make up a chart showing the V gradient split into 3 layers, showing the proportion at each turn due to a) induction from primary b) induction from secondary at modes 1&2 c) induction from secondary at mode 3. That should clarify the picture a little if I can run those for both normal k and high k. More to follow later on this subject. Cheers, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.