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Re: Measuring Coupling Coefficients




From: 	bmack[SMTP:bmack-at-frontiernet-dot-net]
Sent: 	Thursday, November 27, 1997 10:34 AM
To: 	Tesla List
Subject: 	Re: Measuring Coupling Coefficients

Terry

I haven't tried this but...
Considering that  k is not frequency dependant you should be 
able to measure it at a much lower frequency (neglecting capacitive
coupling).
This makes the test equipment loading less important in the calculations.

step1)Measure the inductance of each coil  independantly out of the TC
circuit.
I use a series resonance test w/external cap at some lower RF freq but
close
as possible to the working frequency.

step2) re-assemble TC

step3) set a high undistorted amplitude into a PURE RESISTIVE load of 50
ohms
and make note of this P-P value. Use the same frequency as the prevous
test.

step4) hookup the RF generator across the the primary, again at the same
frequency .

step5) Adjust the secondary Pure resistive load to reflect 50 ohms into the
primary.  At this point it will have the same amplitude as prevously noted.

step6) k=  sqrt(L2/L1)
                --------------------
                sqrt(R2/R1)  

For high powered coils, a lower impedance match for the primary may be
required due to the smaller magnitizing inductance.
In this case a matching transformer could be constructed.

Comments anyone???

Jim McVey






----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Measuring Coupling Coefficients
> Date: Tuesday, November 25, 1997 11:17 PM
> 
> 
> From: 	terryf-at-verinet-dot-com[SMTP:terryf-at-verinet-dot-com]
> Sent: 	Tuesday, November 25, 1997 4:23 PM
> To: 	Tesla List
> Subject: 	Measuring Coupling Coefficients
> 
> "Hi All,
>         I have been playing with measuring coupling coefficients lately. 
I
> was just wondering if anyone has a relatively easy way to accurately
measure
> this elusive factor?" > Very large edit<        Terry"
>        
> 
> 
>