From: "Malcolm Watts"
Date: Tue, 24 Oct 2000 13:04:56 +1300
Subject: Re: [TSSP] NSVPI - Latter Results
With reference to these curves: http://www.abelian.demon.co.uk/tssp-data/nsvpi2210b.gif > > Again the predictions have been adjusted for the slight shift in > Fres, and the measured gradients have been aligned with the centers of > the probe positions. Clearly the predicted gradient peak (the point of > inflection in the V profile) at around 8" coincides nicely with > measurements in both position and amplitude. Below the gradient peak > the voltage rise is concave and in this region the measured gradients > are a little below the predictions. This is probably due to a reduced > external capacitance resulting from the partial ground plane used in > this test setup - the predictions were based on a continuous > groundplane. The extra Cext in the latter case would predict a > slightly higher dV/dx in this region. This seems to have a knock on > effect all the way up the coil, giving a slight skew to the > measurements wrt the predicted curve, and the measured gradient peak > is probably slightly above the predicted peak as a result, say 9". > > All in all this is a very satisfying set of results. From my point of > view as maintainer of the tsim program it provides a much needed > confirmation that both the determination and the application of the > capacitance matrices is not grossly in error. The character of this > voltage profile lies somewhere between that of pn1710 examples 1 and > 9, and the most delightful part is perhaps the clear evidence of the > internal capacitance circulating currents at work here. I'd say there is some evidence here of where racing sparks might occur on an overdriven coil if dV/dx rather than excited spurii is the culprit. Perhaps this is something we could look at more closely later. > Terry, the overall simplicity and effectiveness of this method is > impressive, and I believe your results represent a significant > milestone in making visible the inner workings of the secondary. Hear hear! Regards, malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.