From: Paul
Date: Tue, 21 May 2002 13:12:50 +0100
Subject: Re: [TSSP] Topload breakout potentials
Bart, can you clarify the ID of the primary? You gave the first measurement as > Turn O.D. LuH > 1 11.375 3 so I guess the start of that first turn is about 10.5/2" radius from the center of the coil. If I use this value then your measured inductances compare well with acmi. > I adjusted coupling tonight by raising the primary...So, the > sec is about 0.1875" above primary center plane. > Corona ring dimensions ended up at 4" x 14.875" and a nice fit. > The top 1/3 of the corona ring was actually inside the toroid > and the corona ring bottom plane was 1.375" So that's a second toroid then, the 4" x 14.875" ? John wrote: > I think that in all cases of streamer breakout that I've seen, > the streamers *do* space themselves as far away from each > other as possible. Bart wrote: > I'll second John's observations. Malcolm wrote: > ...just what I've observed in action Well that suggests to me that space charge is definately big enough to significantly affect the surface fields on the topload. Boris wrote: > As I said ,further progress in software should be > expected in lines where software uses experimental > data more than checking them out. Absolutely agree. I think we should try to solve the problem of getting an accurate scope trace from the topvolts. That will allow us to make some empirical conclusions about the breakout dynamics which can then be fed back into the model software. I don't see much hope of us using theory to bypass or predict those topvolts measurements. Even if quantitative theories of streamer formation dynamics exists in the literature, it's highly unlikely that we could apply it in any meaningful way - it would be just too difficult and complicated I think. There are some things we can do though. For example I could put together a program to calculate the effect on the topload surface field of a given pattern of streamers, given some assumption about the C or Q per unit length. Boris wrote: > about corona formative time lags I'm not sure at all. Me neither, but it does offer an explanation for some effects, especially in conjunction with considerations of space charge. For example, if the first streamer forms too slowly compared with the risetime of the topvolts, it might not develop space charge quickly enough to prevent further streamers forming elsewhere, whereas a slower rising topvolts, given sufficient charge reservoir, might be able to form a single long streamer quickly enough to completely suppress further streamers. -- Paul Nicholson, --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.