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Re: Need Help with 15 degree Primary Support System

At 07:14 PM 7/15/99 -0600, Tesla List wrote:

>Original Poster: Esondrmn-at-aol-dot-com 

<snippage>

Hi Ed,

I've seen pictures of your coil and it's awesome!

>Don,
>
>I have a 6.0" diameter secondary with a 15 turn primary made from 3/8" copper 
>tubing with 3/8" spacing.  I originally used a 15 to 20 degree saucer shaped 
>primary and have since replaced it with a flat primary.  I would strongly 
>reccomend a flat primary.  Two reasons, you can easily adjust the primary / 
>secondary coupling just as well with a flat design and as the sparks grow 
>ever longer the elevated primary just gets in the way.  Also, it is easier to 
>build a flat primary.

Construction method noted. Thanks!

The reason I decided to go with the 15 degree primary was based 
upon several texts I have read from the archives, and on Gary Weaver's
tests using a flat, a 15 degree and a 30 degree primary with different
NSTs. In his tests, the flat primary had the least coupling, but virtually
no strikes from the topload to the primary, the 15 degree had the best
coupling with a nominal amount of strikes to the primary and the 30
degree, was over-coupled and also suffered from the most amount 
of strikes to the strike rail. The 15 degree angle seemed sensible
to me and is what I chose to build the supports.

However, I have noted that on all coils over 8" that the primary is
always flat. 

Is the idea of an inclined primary outdated? Is it better to go with
a flat versus an inclined primary on all coil sizes? I suspect this
might be a small controversy given the amount of coilers using an
inclined primary already. The question is,  how much much will I
have to raise the secondary to promote tighter coupling with a
flat primary? Weaver's tests seemed to me to be pretty conclusive.

I agree that it's much easier to build a flat primary. The 15 degree
was giving me grief for trying to figure out how to keep the tubing
_down_ in the slots. I was just about to ditch wood and go plastic
since I could have routed the slots down deeper to hold the tubing
better. I am aware that Gary Lau used Lexan for his support system
and I did consider that but wanted to try wood first. I am also aware
of a Brit that used HDPE cutting boards cut into strips for his flat
primary at http://www.breakfix.demon.co.uk/tesla_primary.html and
it really looks good.

I also read your archived article on building a toroid and chose to
go with a 3" PVC end cap since I want to try different size toploads.
I ended up using flexible aluminum foil ducting with the two inverted
pie pans as the center hub to get a 21x6 toroid. It works great!

Don

--
"In a age of universal deceit, telling the truth is a revolutionary act."
                                 - George Orwell -