Re: More Coupling...

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Ed,

Measured K on my flat primary for my 12.75" x 45" coil.
The flat primary is 16.5"ID, 0.375"wire, 0.625" spacing (c-c) (or 0.375
edge to edge), and 11.6
turns in the case of using my 0.06uF cap setup.

I used a method of measuring I believe Terry posted a couple years ago.

Measured current of primary using a hair dryer in series (10.95A). Then
measured secondary
voltage (secondary + 1uF cap + 18k ohm in series) at 2.59V.

Mutual Inductance M = V / (377 * I) or 2.59V / (377 * 10.95A) = 627.4 M

K = M / sqrt(Lp * Ls) = 627 / (107.13uH * 87.6mH) = 0.205 K

Anyway, that's K on that day. I am only aware of one program that calc'd K
but it was
preliminary and I haven't heard anything about it in a "long" time.
Measuring is pretty easy and
can be done with a simple DMM.

Bart

Tesla list wrote:

> Original poster: "Ed Phillips by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
>
> A friend of mine built such a high k system at TRW, in connection with
> a million-volt (really 10^6 volts) pulse project.  It worked OK but was
> a lot of work to get set up right.  Do you know of any approximate
> method for calculating the mutual inductance for a flat primary?  I
> suppose one could do it by computing M for each of the turns and then
> summing it, but that sounds like a lot of work and have never tried it.
>
>         I see a lot of fellows using flat primaries, and wonder how much
> coupling they actually get.
>
> Ed