Re: Wire length (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 18 Dec 2006 18:57:28 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Wire length (fwd)

Cool Jared. No hurry's on the explanation, so take the time needed, and 
thanks for the status.

I've been building another flat coil this last month. It's sort of a 
Tesla duplicate, but scaled down (the original is just not practical for 
my garage). Here's the layout I came up with.
http://www.classictesla.com/flat/Bigflat.gif

It's inductance should be 4.165mH at Ldc and 4.85 at resonance (76.3pF 
at Cdc and 54.9pF at resonance) including top load and primary.

I'm giving it an authentic Tesla look with wooden runners, however, the 
runners will incorporate a standoff design which Tesla did not have 
privileged to.
http://www.classictesla.com/flat/flatrunner.gif

The design will attempt a 5" sphere terminal. The primary will be flat 
copper ribbon around the perimeter of the secondary. The loaded Q is 
modeled at 713. It's a bit different than my flat closewound coil, so it 
should be a lot of fun to play with and to see what I can do with it. 
This flat coil will also be driven with Terry's SISG circuit (I bought 
enough of these nice SISG boards from Mark Dunn with this in mind). I'm 
doing this for the fun of it and no other reason. But, as with all my 
coils, I will also make as many measurements as possible to add another 
little piece of the puzzle to our very unique craft.

I've already built all the wooden runners (complete with plexi standoff 
groove, etc.). I've also completed the mounting of the long runners to 
center disc as well as the long runner plexi standoffs (shorter runner 
standoffs is all that is left to start winding). One thing I realized 
with Tesla's flat coil is that he used wooden slats behind the coil to 
mount the runners (every pic of Tesla's flat coil shows the same wooden 
slats). I will do something a little different to adhere the 
intermediate runners (I just don't want all that wood behind the coil). 
I expect soon after Christmas, I'll finish the flat coil and can begin 
work on the primary and driver circuit (I already have the copper 
ribbon). The driver will have to wait on IGBT's (the price doubled, so 
I'm looking for either alternatives or lower prices for the same through 
other distributors). I plan on supporting the coil with a camera type 
tripod (where the coil can be angled vertically, horizontally, or 
wherever) to give you a vision of the end look I'm hoping to achieve.

Anyway, knowing that you have built many flat coils (and other 
wavelength coils), I thought I'd share this latest adventure. BTW, I 
expect flashover to be much less a problem with this spacewound coil 
than with closewound flat coils as has been my experience. Oddly, I 
actually found flashovers on closewound coils pretty cool to watch 
(well, until outer windings burned, which I then realized I had gazed at 
it just a little too long). Still need to fix that coil.

Take care,
Bart

Tesla list wrote:

>Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Mon, 18 Dec 2006 17:32:05 -0500
>From: Jared Dwarshuis <jdwarshuis@xxxxxxxxx>
>To: Pupman <tesla@xxxxxxxxxx>
>Subject: Wire length (fwd)
>
>Having built some rather short half wave coils, I can say for sure that a
>flashover from end to end of the coil can happen just as readily as a
>primary strike.
>
> I am still working on a laymans explaination for the physics of multiple
>wavelength coils, maybe a few days.
>
>Jared
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