From: Paul
Date: Sun, 12 May 2002 18:43:09 +0100
Subject: Re: [TSSP] Topload breakout potentials
John wrote: > I have a 6" x 24" smooth toroid, but it may be too large? The 6" x 24" toroid drops the Fres of TT42 down to around 143.5 kHz from its former 192 kHz. The surface gradient for this larger toroid is 0.036 V/cm/V compared with 0.051 V/cm/V for the existing upper toroid. The total Cee of the resonator is 33.4pF so keeping the same bang size would give a new top volts of sqrt( 2 * 4J/33.4pF) = 490 kV which compares with 380 kV for the de-tuned existing setup and a possible 590kV if tuned for the smaller topload. The 490 kV gives a surface field of 0.036 * 490 = 18 kV/cm which ought to hold back the breakout for longer. The only trouble is that the primary probably won't tune this low. I'm not sure how many more turns you have beyond 14.5, but you'd need around 40% more primary inductance. Whether the secondary would also take the extra 490kV/380kV = 30% higher voltage gradient is a further question. John wrote: > It seems that Malcolm's toroid on his coil has such a large ROC, > that it may be tuned correctly, yet still barely breakout. This > may be why he's getting such good results. It would be interesting > to see if Malcolm's coil's tap points, etc. indicate a perfect tune > between pri/sec. Yes. I don't think I have the details of Malcolm's coil. It would be a good idea to go through all four of these coils and make an accurate model of each, and to confirm a few things with some measurements so that we know for sure that the model is representing the tuning of each coil properly. -- Paul Nicholson, --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.