Re: THOR's strike rail: how to?

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

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