Re: Recycled: Measuring Coupling Coefficients

From: 	bmack[SMTP:bmack-at-frontiernet-dot-net]
Sent: 	Sunday, December 07, 1997 1:47 PM
To: 	Tesla List
Subject: 	Re: Recycled: Measuring Coupling Coefficients


The equation you cited as an "exception" : k=1/sqrt(QpQs), is for 
CRITICAL COUPLING k.  It's intended use is to optimize the coupling
to avoid overcoupling the system which produces two "humps" on
one above and below resonance.  This is a different issue than calculating
the actual value, irregardless of it's effect on the system.

Hope this clears it up.

Jim McVey

> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Re: Recycled: Measuring Coupling Coefficients
> Date: Sunday, December 07, 1997 10:27 AM
> From: 	John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
> Sent: 	Sunday, December 07, 1997 1:22 AM
> To: 	Tesla List
> Subject: 	Re: Recycled: Measuring Coupling Coefficients
> At 05:41 AM 12/6/97 +0000, you wrote:
> >
> >From: 	Mark S. Rzeszotarski, Ph.D.[SMTP:msr7-at-po.cwru.edu]
> >Sent: 	Friday, December 05, 1997 6:57 AM
> >To: 	Tesla List
> >Subject: 	Re: Recycled: Measuring Coupling Coefficients
> >
> >Hello All,
> >    
> -------------------------------- snip
> >        K depends only on geometry.  M, Lp and Ls depend only on
> >The equation above considering the two Q factors is the value of K one
> >should strive for for maximum energy transfer between the primary and
> >secondary.  Of course, you also want that to be equal to one of those
nice K
> >values where all of the energy happens to be transferred to the
> >when the gap turns off (1st, 2nd or 3rd notch, generally).  In addition,
> >may want to match Qp to Qs under full firing conditions.  To do this you
> >must measure the load Q of both circuits during spark production.
> >        You can precalculate M and K quite easily using Neumann's
> >It is a slow numerical integration, but yields accurate results.  The
> >series approximation described in Grover's Inductance text is inaccurate
> >typical tesla coil geometries.  I have written the numerical integration
> >code, and it is fairly straightforward.  It has worked well for me for
> >solenoidal and flat spiral primaries, and gives an approximate solution
> >inverted cones.  (M is accurate, but Lp is approximated.)  I plan to
> >the program to the net after some more fine tuning.  It is in beta
testing now.
> >Regards,
> >Mark S. Rzeszotarski, Ph.D.
> -------------------------------------------------------------
>   Mark -
>   As I mentioned in an earlier post the K factor appears to be related
> to the physical characteristics and geometry of the coil. However, this
> appears to be contrary to    K = 1/sqrt(QpQs)    and    Q = 6.283 F L
> where the K factor is related to the frequencies, unlike the other K
> equations where the frequencies cancel out. Do you have a an explanation
> this apparent contradiction ?
>   The transfer of energy between the two coils is always 100% and purely
> inductive. The K factor only affects the time for the total transfer.
> are, of course, losses due to currents in the windings. These losses do
> affect the transfer which is inductive and reactive with no losses. 
>   The JHCTES TC computer program determines the mutual inductance from
> physical characteristics and geometry of the coils. It also calculates
> Lp and Ls using the Wheeler equation so the K factor can be found. This
> method has been found to closely agree with K factor tests when properly
> performed. The program also calculates and coordinates 46 of the major
> coils parameters while keeping the complete system in tune.
>   The Tesla List will be looking forward to your Neumann numerical
> integration computer program.
>   John Couture