From: "Malcolm Watts"
Date: Fri, 29 Jun 2001 08:58:06 +1200
Subject: Re: [TSSP] Toroid breakdown voltage indirect meas.
Hi Paul, On 28 Jun 01, at 11:30, Paul wrote: > I wrote: > > > > Is this caused by corona forming on dust or smoke in the air > > > around the topload perhaps? What color - not blue I hope? > > Malcolm Watts wrote: > > > In answer to the first questions, no. Blue is indeed the colour. A 9" > > sphere on the coil of mine produced a ball of cold streamers around > > 3' in diameter. Very faint. Again I initially thought it was some > > trick of the light - until I realized there was no other light source > > to account for it. > > Most odd. Perhaps this is the real breakout threshold, just that > the available streamer current isn't enough the heat things up to > clear visibility. Is the radius of the 'aurora' similar to that of > the eventual streamers? Perhaps this is occuring on Thor as well, > which, if the sums are correct should occur at 440kV, thus around > 14.7kV feed voltage. A completely dark room for the topload and > a photo-multiplier or a long exposure camera would sort the matter > out. It is very close to what one would consider to be the breakout threshold. That is defined by most people seeing visible streamers which in effect is the "ball" coalesced into one or a few definite channels. Actually, I had secretly planned to photograph this with a bulb shutter and make it one of the items on my webpage when I eventually get around to building one. (aside - instead of repeating ad nauseum what others have done in theirs, I want mine to show things new). A time exposure should show a solid blue glow around the terminal. So much for novelty. > Certainly an interesting phenomena which we ought to try to > understand. Thanks for bringing it up - I'm sure all will agree > that it is very much on-topic. > > Cheers, > -- > Paul Nicholson, > Manchester, UK. > -- A thought on Bert's post re multiple streamers from HF systems - we may be seeing the effects of discharge channel inductance at these frequencies (dV/dt's). ? Regards, malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.