RE: Mutual inductance and K factor

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

Original poster: "J. B. Weazle McCreath by way of Terry Fritz <twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>


At 05:07 PM 24/10/01 -0600, you wrote:
>
>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<couturejh-at-telocity-dot-com>
>
>Weazle -
>
>Thank you for sending me the test data from your coil. I am aware of Terry's
>method for finding the mutual inductance but I am not very familiar with the
>typical calculations. My notes on his method are buried somewhere in moving
>boxes and I do not have his address for the test.
>
>Your caculations appear to be incorrect in that the mutual inductance should
>reduce instead of increase when the secondary is raised.  Also, are your
>coils pri to sec distance (1.0) and the pri inside radius (3.05) and outside
>radius (7.55) of the used turns agreeing with the program outputs?
>

<snip>

Hello John,

Read my message again; I move the primary, NOT THE SECONDARY, to make
changes in my coupling.  Raising the primary increases the coupling,
just as the figures I sent you show.  The figures for the tightest
coupling, that is the last line of the four, is when the bottom turn
of the secondary is level with the inner-most primary turn.

As to the radius of the inner-most and outer-most (used) primary turns,
I think they are fairly close, but I will confirm that for you later.
My coil is in my shop which is 100 feet from the house and it's just
chucking it down with rain here at the moment, so it won't be tonite!


73, Weazle, VE3EAR/VE3WZL

Listening: 147.030+ and 442.075+
E-mail:    weazle-at-hurontel.on.ca
           or ve3ear-at-rac.ca
Web site:  http://www.hurontel.on.ca/~weazle