RE: K Factor & Mutual Inductance

        RE: K Factor & Mutual Inductance
        Thu, 3 Apr 1997 16:08:32 -0500
        Heinz Wahl <hwahl-at-jtc-campus.moric-dot-org>
        "'Tesla List'" <tesla-at-pupman-dot-com>

I agree Ed, but what happens to k as Lp gets saturated? If Ls core is
larger and the area of saturation is in a fraction of that
core, as in a TC, wouldn't there be a point of diminishing return for
the energy applied? Couldn't that be misconstrued as a
bend in the upper end of Lm & k?


From:  Tesla List [SMTP:tesla-at-pupman-dot-com]
Sent:  Thursday, April 03, 1997 12:24 AM
To:  tesla-at-poodle.pupman-dot-com
Subject:  Re: K Factor & Mutual Inductance

        Re: K Factor & Mutual Inductance
        Wed, 2 Apr 1997 18:01:13 -0800 (PST)
        "Edward V. Phillips" <ed-at-alumni.caltech.edu>

" is found the K Factor can be found by the equation
>           K Factor = Lm/(sqrt(LpLs))
> where Lp and Ls are the inductances of the primary and secondary coils.

That equation is good for any coil - air-cored, iron cored or
whatever? There are no conditions stated by Terman or anyone else to
my knowledge (except JHC perhaps ;)

> Note that the K Factor or coupling is not only dependent on the physical
> location of the coils but also on several other parameters such as
> resonant
> frequency, Q Factor, log decrement, etc.

Where is the frequency dependence in that equation? Lp? Ls? M? k? I've
not observed any frequency dependence in Lp or Ls from DC to TC
frequencies in all the measurements I've done. So it must be in k or
M, right? But what defines either of those? Is the number of flux
linkages between two coils frequency dependent? Why?"
        The coupling factor is independent of frequency, Q, etc.
the definition is exact (for coils inductively coupled coils).