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Re: Primary Coil wire type





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> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Primary Coil wire type
> Date: Sunday, April 11, 1999 2:02 PM
> 
> Original Poster: Doug Brunner <dabrunner-at-earthlink-dot-net> 
> 
> I'm assuming your coil is under about 1.5kVA. The 1/4 in. solid copper is
good.
> However, for a bigger coil, you want to use tubing, because current flows
> mainly
> on the outside, and that way you have two surfaces to work with and the
> interior
> is not wasted.
You still have only one surface for the current to flow on. None will flow
on the inside of the tubing. The whole thing about skin effect is that the
current all flows in the outer layer (thickness depending on electrical and
magnetic properties of the material). So, you might as well not have the
inside there. Since copper is expensive, and, it would be a real challenge
to bend 1" diameter bar stock into a flat spiral primary, as you get
bigger, you go to tubing (which is also readily available everywhere, as
opposed to the bar stock).
>