Re: THOR's strike rail: how to?

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

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