Re: Dual layer primaries

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

Original poster: "Kurt Schraner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <k.schraner-at-datacomm.ch>

Hi Jason,

...just to be aware: in order to have the combined inductance supported
by the mutual inductance M [with M=k*sqrt(L1*L2)], you should not wind
the 2 pancake coils in the same direction (i.e. clockwise), but in
opposite directions (one clockwise, the other couterclockwise), presumed
you connect the inner turns. In the first case(=yours) you have:

Ltotal = L1 + L2 - 2*M

in the second case:

Ltotal = L1 + L2 + 2*M

...which I "think" is, what you like. A 3D-hand sketch, with magnetic
field line directions entered, can make it clear.

Cheers
        Kurt Schraner


Tesla list wrote:
> 
> Original poster: "Jason Johnson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>
> 
> Hello,
> 
> Does anyone have any idea as to how to calculate inductance for a two level
> primary? I'm talking about a primary coil that is wound with two layers both
> going the same direction and seperated by an inch or so, inner turns
connected
> together, and tapped in two places, one on the bottom half, one on the top
> half. I know that I can't just calc. for one primary and then double it,
> because the halves are going to have some mutual inductance, resulting in a
> higher overall inductance than just doubling one of half the size, right?
Does
> anyone get what I'm talking abut here?
> 
> <<Jason Johnson>>
> The Geek Group
> G-3 #1129
> <http://www.thegeekgroup-dot-org/>http://www.thegeekgroup-dot-org/