Re: Dual layer primaries

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: "Jason Johnson" <hvjjohnson13-at-hotmail-dot-com>
> 
> 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?

In the general case, given L1 and L2, inductances of the two coils, and
k, their coupling coefficient, the total inductance would be
Ltotal=L1+L2+2*k*sqrt(L1*L2).
If the taps are at the same radius and the distance between the coils 
is small, a good approximation would be to compute the inductance of 
a single coil and multiply it by -four-.

Antonio Carlos M. de Queiroz