Re: THOR's strike rail: how to?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Joe,

My view on a strike ring is sweet and sour. Yes, it's an rf ground partial
loop typically mounted
slightly above the outer primary winding. Should a strike seek the primary,
it will hopefully find
the strike ring. Many times it does, but I think it probably attracts some
of the strikes as well.
Adding another loop near primary center winding will just increase this
affect (my opinion). I would
rather the strike ring take the hit instead of the primary, but I don't
necessarily want to attract
strikes (some of which may hit the primary anyway).

Take care,
Bart

Tesla list wrote:

> Original poster: "Joseph M. Geiss by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <joseph20-at-home-dot-com>
>
> Correct me if I am wrong but all a strike ring is, is a grounded
> partial-circle of conductor above the
> primary. Why could you not put another ring half the distance from the edge
> of the primary and the wall
> of the secodary so you now have a strike ring running above the middle of
> the primary?
>
> Joe
>
> Tesla list wrote:
>
> > Original poster: "Malcolm Watts by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> >
> > Hi Marco,
> >
> > On 21 Jun 01, at 7:53, Tesla list wrote:
> >
> > > Original poster: "Marco Denicolai by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <marco.denicolai-at-tellabs-dot-com>
> > >
> > > Hello all (again),
> > >
> > > As you have maybe read, I came to the conclusion that Thor's strike rail
> > > arrangement needs some modification. I had last week a streamer hitting
> > > the primary, with catastrophic effects on one of the CCPS drivers. That
> > > wasn't exactly a nice thing...
> > >
> > > You can see my strike rail + primary at
> > >
> > > http://www.saunalahti.fi/dncmrc/thorpict.htm
> > >
> > > Relevant dimensions are as follows (in mm):
> > >
> > > Primary Height (Inner Turn) = 0
> > > Primary Inner Diameter = 600
> > > Primary  Outer Diameter = 1100
> > > Strike Rail Height = 150
> > > Strike Rail Diameter = 1300
> > > Secondary Base Height = 200
> > > Secondary Diameter = 400
> > >
> > > I can see three solutions, or a combination of them:
> > >
> > > 1. Create a small protuberance on the toroid to originate all streamers
> > > from a known place. I had for a long time a copper bar sitting on the
> > > toroid: never got a streamer getting to the wrong place
> > >
> > > 2. Vary the strike rail dimensions, height, shape. I have a preatty wide
> > > area to shield and I don't like the secondary to arc to it. Seems a not
> > > so easy task.
> > >
> > > 3. Place a 20 mm thick PVC disk (actually, two half-moon sections bolted
> > > together) with some spacers to sit on the top of the primary (maybe at a
> > > realtive height of 100 mm). Easy to do, also because I don't need
> > > frequently tuning. Question: would the lost streamers then hit the
> > > secondary base ?
> > >
> > > What is your opinion? Please, let me know.
> >
> > I think the streamers would probably track around the cover if they
> > seriously head in that direction. Nothing short of a totally bottled-
> > in primary would work in my opinion. You might consider using a
> > driver transformer to feed the resonator in a magnifier type setup
> > which would make isolating the secondary discharges a lot easier. A
> > primary residing inside the resonator coilform Electrum-style might
> > also be a better proposition. A disk of plexi mounted inside the
> > coilform to isolate it from the higher voltage portions might also be
> > necessary if you go this route.
> >      A further possibility (a favourite of mine) is to use a bundled
> > primary - say two or even three layer "flat" spiral which compacts Lp
> > into a much smaller volume and would make it less attractive to
> > secondary strikes. Much smaller diameter and much cheaper copper
> > costs too.
> >
> >       Also, congratulations on obtaining your degree. I tried to
> > download your thesis for reading yesterday but ran into problems.
> > I'll try again shortly.
> >
> > Regards,
> > Malcolm