Re: Four Layer Coil

Subject:       Re: Four Layer Coil
       Date:   Sun, 15 Jun 1997 11:56:54 -0700
       From:   Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization:  Stoneridge Engineering
         To:   Tesla List <tesla-at-pupman-dot-com>
 References:   1

Tesla List wrote:
> Subject:  RE: Latest magnifier results - wire shape
>   Date:   Sun, 15 Jun 1997 07:33:38 +0500
>   From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
>     To:   Tesla List <tesla-at-pupman-dot-com>
> On Fri, 13 Jun 1997 22:40:13 +0000 Bert Pool
> <bertpool-at-flash-dot-net> wrote;
> > I covered this in earlier posts, but here it is again.
> >
> > We wound our first layer exactly as always.  The second layer over
> > over the first - same direction.  You'll find that it is very
> > important that there be NO gaps in the underlying layer or you will
> > have problems with the next layer.  We did a total of four layers.
> > Next, we soldered all four wires together.  In effect, the four coils
> > are in parallel.
> It would see to me that placing the layers in parallel you would be
> decreasing the inductance, ie.
>  Total I = 1 / (1/Ifirstlayer) + (1/Isecondlayer)...+(1/Inthlayer)
> Are you saying that even though it reduces the inductance it is still
> a gain over using the equivelent larger gauge wire?


By having the wires of each layer right above the previous layer, there
would be minimal change in the overall inductance of the secondary. The
current in the secondary would be be shared approximately equally
amongst the wires - sort of like using a rectagular-shaped Litz wire.
Winding a secondary with Litz wire will not dramatically change its
inductance versus a coil wound with the same number of turns of magnet

Like with Litz, skin effect losses are reduced since the wires are
insulated from each other. However,  proximity losses would limit the
benefit of further increasing the nuber of layers. Bert's approach
certainly would seem to permit packing significant inductance while
reducing losses that would otherwise occur with the use of smaller
wire.... and you can't argue about his results!  :^)

-- Bert H --