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Re: Oil filed magnifier drivers



Tesla List wrote:
> 
> Subscriber: FutureT-at-aol-dot-com Tue Dec 31 23:03:01 1996
> Date: Tue, 31 Dec 1996 15:38:39 -0500
> From: FutureT-at-aol-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Re: Oil filed magnifier drivers
<SNIP>
> 
> <<We have learned the following:
> 
>  <1. If you try to couple the primary very tightly to the secondary in a
>  magnifier, extremely heroic efforts at insulation will be necessary.
> 
>  <2. Multilayered mylar CAN provide sufficient insulation, but your
> insulation
>  <will have to be much longer than you would ever expect in order to prevent
>  <arc-around thru the oil or along the surface of the mylar.
> 
>  <3. By the time you build sufficient insulation clearances, the driver will
>  <end up as large as a conventional driver (i.e., a Hull type), and you have
> <to reach down elbow deep in transformer oil to change your taps when you
> < tune - a very nasty disadvantage.
> 
> <4. A magnifier driver really needs the primary on the outside, readily
>  <available for tap changing, instead of in oil, but special arc shields
> would
> <have to be made to prevent arc-around from secondary to primary, again
> < making the driver bulky.  I suspect these shields would be plexiglass disks
> < about 30 inches in diameter, 1/2 inch thick - not cheap!
> 
> < 5. Oil filled magnifiers are messy, very heavy (over 100 pounds), slippery,
>  <expensive, and they are very hard to make work.
> 
>  <We have now placed our oil filled magnifier carcass on top of the pile of
>  <dead poly capacitors and neon transformers in the back corner, at least for
>  <now.
> 
>  <<We have already started to design a conventional magnifier driver based
> upon
>  <Richard Hull's Maggie 11-E.  The driver will be bigger than we'd like to
> <have, but we know it will work (yea, rah Richard!)
> 
> < Building a serous oil filled magnifier driver was an interesting
> experience,
>  <but it is not something I'd recommend anyone try.
> 
> 
>  <Bert Pool and Wild Bill Emery.
> < nikki-at-fastlane-dot-net
>   >>
> 
> Thanks bert for the info, I can see this was a fun project!!   BTW, Lou
> Balint of PA has built various oil insulated magnifier drivers, and obtained
> at least 42" sparks, he used ferrite as an additional aid for increasing the
> coupling, resulting in coupling of  k = .7.  I'm not sure if k = .7 was the
> final successful arrangement.   His coils were cylindrical, with the primary
> outside of the oil.  A unique feature of Lou's system was that his SECONDARY
> was "tuned" using an external oil emersed variable capacitor.   I can obtain
> the full details of the project from Lou if anyone is interested.
> 
> John Freau

I'm interested. BTW, can you talk Lou into joining the list??

-- Bert --