TSSP: List Archives

From: Paul
Date: Sun, 30 Jun 2002 18:52:53 +0100
Subject: Re: [TSSP] Re: Top V Probe Design

Bart wrote:

> I too have been super busy the past couple weeks...

Ah good.  Then I don't feel too bad.  I'm one of those 
that can't make much progress with half an hour here, an
hour there.  Have to put in those long sessions to get
absorbed into a problem, and there just hasn't been the
chance lately.  Nice new machines at work which need to be
brought to life with some well-sorted software.

Still, light at the end of the tunnel now.

Well I still don't know about this probe design of Terry's.
On paper it looks to be only good to a fairly limited voltage,
but then it all depends on how conservative you are with 
estimations of the breakdown field of an unknown oil. 
Maybe the thing to do is just build it and see how it does?

I wrote:
> V = 0.0381 * 6000 * ln(0.0762/0.0381)
>   = 158 kV

If in practice it'll take 300kV, then that ought to give
breakout from a reasonable sized toroid I would have thought?

I haven't been able to come up with anything better.

Thanks for the close look at that Jennings.  I see there is
no outer shield electrode, so the thing is only accurate when
remote from everything except the electrode being measured, so
wouldn't do too well inside a coil!

And there are plenty of blanks in the data summarised in
  http://www.abelian.demon.co.uk/tssp/cmod/
so if anyone has any new measurements (Lpri,Fpri,Fsec,Ldc) let
me know.  There's also quite a big discrepancy in John's primary
inductances which needs to be ironed out.  So far the only 
one of the coils with a reliable model is Bart's.

Bart, the entry for your coil ba0 in the above table applies
to the system following your modifications.  But does the
description of breakout still apply - I think you said the
racing arcs had gone away, and from your pictures it looks like
you now have three or four streamers of some length, rather than
multiple short ones.

BTW, I notice in one of Bart's pics, a good demonstration of 
the streamer roots positioning themselves just about at 90 deg
intervals - as far away as they can, around the perimeter of
the toroid.

Anyway, the top item on my stack is finishing some notes on
the qvar experiments...

Cheers All,
--
Paul Nicholson,
--


Maintainer Paul Nicholson, paul@abelian.demon.co.uk.