Re: "De-coupling" coefficient?

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

Original poster: "Malcolm Watts by way of Terry Fritz <teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jolyon,
            It seems to me that you are trying to introduce
unnecessary complications:

On 2 Jul 2003, at 7:50, Tesla list wrote:

 > Original poster: "Jolyon Vater Cox by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >
 > I am interested to know how k,the coupling coefficient, affects the value of
 > the load impedance referred back to the primary across the turns ratio when
 > the transformer is not "ideal".

It obviously makes the reflected impedance higher than if k = 1.

 > If the term k represents the fraction of the total flux which is common to
 > both windings (the coupled flux)
 > there must be another term  say, l, for the remaining fraction which
 > represents the flux which is not common to either winding (the leakage
 > flux).
 >
 > Since k is the coupling coefficient  would it not be natural for l the be
 > termed the de-coupling coefficient?

Again, what's the point? k does the job all by itself.

 > Speaking of a mechanical analogy (perhaps not strictly accurate) is it not
 > possible to view transformers as "gearboxes" for electrical energy
 > the ideal transformer being akin to a ideal gearbox with unity coupling i.e
 > zero slippage between the gear teeth whereas  real transformers and
 > gearboxes are less than ideal exhibiting finite slippage?

That analogy has been around for decades if not centuries. The
correspondences are obvious.

 > And if it is permissible to speak of a de-coupling coefficient, would it not
 > be possible for the new term to be be used to derive the value of leakage
 > inductance from the values of the primary and secondary inductances.

You don't need a new term. Current formulae already give adequate
means to define/measure leakage inductance. I gave a formula relating
M and k several posts ago. That which is not mutual must be leakage.
If such terms as you are attempting to introduce were necessary for
transformer design, they would have been introduced more than a
century ago.

Malcolm