# Re........ Measuring Coupling Coefficients

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From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Thursday, December 11, 1997 3:36 PM
To: 	Tesla List
Subject: 	Re: Re........  Measuring Coupling Coefficients

Sorry all, but I cannot let this go....

> From:   John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
> Sent:   Wednesday, December 10, 1997 6:04 PM
> To:     Tesla List
> Subject:     Re........  Measuring Coupling Coefficients

<snip>

>   Malcolm, All -
>
>   Kc equals critical coupling.

Kc does not equal critical coupling. Kc is a number intimately
related to the aggregate coil Q's.

> Coupling is a percentage of flux linkages. At
> critical coupling (Kc) the mutual reactance is Xm = sqrt(Rp^2+Rs^2). The
> Xm,Rp, and Rs are in ohms, but the Kc is not in ohms and ,therefore, not
> "LOSSES". The Kc is still only a percentage of flux linkages.

Nope - see the bit at the end of this piece.

>   But if, as you say, the   K = 1/sqrt(QpQs)   only occurs at Kc then
> critical coupling is dependent on frequency. In other words K is dependent
> on frequency when the coupling is equal to a certain percentage of flux

I didn't say that at all. I said that *at critical coupling, kc = k*.

>   This leaves the question "What is there about frequency and Q factor that
> affects coupling only at a certain percentage of flux linkages?" To me this
> means that with a Tesla coil there are lines of magnetic force from the
> primary and secondary coils that when a certain percentage of these lines
> are linked the frequency is involved. At other percentages the frequency has
> no effect.
>
>   Now that K can be found without building any coils, does anyone want to
> set up a program to find the critical coupling of a series of different TCs
> to research the above? The parameters would include K, Lm, Lp, Ls, Q, F, Rp,
> Rs, etc. We may find that TC output (sparks) can be increased even more than
> what we are doing now.
>
>   John Couture

Electricity 1:   Suppose Q1 = Q2   (just to make it obvious)

Then:  1/SQRT(Q1.Q2) = 1/SQRT(Q1^2)  = 1/Q1 = *THE DISSIPATION FACTOR*

What has that got to do with flux linkages??????

Malcolm

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