Re: Calculating and Measuring Resonant Frequency / Inductance of Secondary Coil (magnifier)

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

Original poster: "Bart Anderson" <classi6-at-classictesla-dot-com> 

Hi Dan,

Yes, understood. I can measure the split as well as the individual
frequency's as long as as I short across the coil. For example, to
measure Fres of L2 minus the split, requires L3 to be shorted across
the coil(still connected to the top of L2). This effectively removes
the split and still keeps L3 and the toploads C in place. Fres measured
185 kHz, close to a calculated 181 kHz, so that works well.

Take care,
Bart

 > Original poster: dhmccauley-at-spacecatlighting-dot-com
 >
 >
 > Bart,
 >
 > That is completely normal for a magnifier and even a classic coil.
This is
 > known in simplest terms as "frequency splitting" and occurs whenever
there
 > are
 > multiple resonant networks within a system.  This effect is less
obvious in
 > classic double resonant tesla coils as the coupling is much lower.
(The
 > lower the
 > coupling, the closer the frequency split humps are closer to
the "natural"
 > frequency of the individual tuned (isolated) circuits.  With a
magnifier,
 > the coupling is much
 > higher and the frequency split humps are much further away from the
 > independent natural frequencies of the individual resonant networks.
 >
 > Dan
 >
 >
 > Hi Dan,
 >
 > Good point and true. I performed my setup by making all 3 coils the
 > same. I started measurements last night. There are some interesting
 > scenario's with magnifiers, and especially in my little situation. For
 > example, although all 3 are at 180kHz on my own, with the extra coil
 > over the driver, when the base is driven I'm meausuring 142 kHz (i.e.,
 > 2 coils in series and a single topload affecting both). That kind of
 > thing. Fun stuff! I'll post details once I have them.
 >
 > Take care,
 > Bart
 >
 >
 >
 >

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