From: "Terrell W. Fritz"
Date: Fri, 20 Oct 2000 17:25:20 -0600
Subject: Re: [TSSP] Progress report 18th Oct 2000
Hi Paul, At 11:43 PM 10/20/2000 +0100, you wrote: >Terry wrote: > >> "I" would like to see the capacitance per unit length graph and >> it's bathtube curve. > >OK, I've added another section to pn1710 in > > http://www.abelian.demon.co.uk/pn1710/ > >Current version is now 0.2b. NEAT!! Thanks a bunch! That is the right curve too :-)) > >> Can you do more than 32 points? > >Yes, if necessary, but since Cint is 2D, the time taken to compute >the capacitance matrix is proportional to N^2. > >The number 32 of cylindrical electrodes into which the coil is >broken for capacitance matrix estimation is a compromise between >speed and accuracy. I figured 32 would give about 3% error in >resolution, therefore 1.5% error in Fres. It takes between 2 and >4 pentium-cpu-days to produce the Cint and Cext matrices from a coil >description, about 4hrs on the cluster. The new solver will require >only a third the cpu time, but I think I'll use that gain for a >speed up rather than more resolution in order to explore lots of >geometries. Great, no problem! As long as it "can" do more points, one with a lot of spare time can investigate this. You may try 16 points just to be sure the error stays within the predictions but if you feel comfortable, so do I. I just worry that the very high initial and final capacitance (of just the first and last turns) could be having a sever affect. But to really pin that down might take 1024 points :O > >> I worry that the top and bottom numbers may get "averaged" >> excessivly from their true spikyness. > >I agree. Nothing much happens to Cext along most of the length so >maybe a varying segment length could be applied but this would be >tricky to add to Cint. I wouldn't want to try it without some >evidence that the existing lack of resolution at the ends was causing >a problem. With Cint, which is a function of two points on the coil, >the resolution is also lacking when the points are close together. >This causes the flat top to the example slice through Cint in pn1710. I am working on my great secondary voltage profile probe today. So far it does not affect secondary frequency which is a great hurdle. Know I just have to get the "right" information out of it... Last night's idea fell apart but this new one looks good. Current measurements at many points along the secondary is also very possible but will take much work. Tiny fiber-optic current transducers could do it but that means a special coil and a special current probe... I'll try to get what I have working first. Thanks again for the capacitance profiles. You don't know how much time I have spent trying to figure such things out... Cheers, Terry > >Cheers, >-- >Paul Nicholson, >Manchester, UK. >--
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.