Re: Making Flat secondaries - disaster #1...

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Glass is pretty flexible.....especially if you are trying to hold the bend
to less than thickness of a wire over a foot (look how much the walls of an
aquarium bow out, under relatively low pressure). What you want is ribs that
keep the plate from bending.  A friend who makes all sorts of weird
mechanical stuff (like wrought iron spirals) suggests fairly thick steel
plates (to him, that probably means 1/2" or more) and a suitable spacer in
the center.  Another approach is to glue up some acrylic or polycarbonate:
Big disk or plate with lots of stiffening ribs (at right angles).

Maybe you should resurrect your computer controlled winding machine, and
just lay the windings down like grooves on a record mastering machine. That
way, you won't have any radial compressive loads, which is probably what
causes all the problems.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, February 15, 2002 6:53 PM
Subject: Making Flat secondaries - disaster #1...


> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
> Hi All,
>
> I worked on my new flat secondary tonight and I wanted to warn you 'not'
to
> try this method ;-P
>
> I took a sheet of 18 x 18 inch plate glass 1/4 inch thick and I glued a
1/4
> inch brass bolt to the center with silicone.  I got a big "Lazy Susan"
turn
> table bearing to rotate the glass on.
>
> The plan was to use double sided tape on the glass to hold the #24 wire
> windings as I turned them to place:
>
> http://hot-streamer-dot-com/temp/flat0.jpg
>
> Once done, I could spray coat it to make it stronger.  An alternative was
> to use spray adhesive in place of the tape.
>
> This is how it turned out:
>
> http://hot-streamer-dot-com/temp/flat1.jpg
>
> I think the inductance is sort of low :o))
>
> The basic materials are all sound but the #24 wire could easily pull away
> from the tape in large chunks.  The tape was no match at all for the
> stiffness of the wire.
>
> "Next", I am thinking of using a second sheet of glass (I really worry
> plastic will not be stiff enough) and spacing it at 21.5 mil to wind the
> coil between the sheets.  I will probably have to glass drill a hole in
the
> sheets for the terminal and bolt to hold the sheets together.  Wow!!  I am
> really looking forward to drilling the glass =:O)))  The winding will have
> to be loose enough so as not to press against the sheets too much.  A tiny
> bit of pressure from each wind could add up to a ton (maybe literally)
when
> 500 winds are in place.  One disadvantage of having the wire between
sheets
> is that I can't probe it for secondary voltage profiles.  Maybe not a big
> deal since Paul's programs are real good :-))  I sort of wonder what
effect
> the coil holding forms will have on the coil...
>
> Cheers,
>
> Terry
>
>
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