Re: A new Tesla coil and k measurements

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

Original poster: "Paul Nicholson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Antonio,

Putting in your dimensions to tssp gives:

  Fpri: (with secondary removed) 295.5 kHz;
  Fsec: (with pri gap open) 293.0 kHz (1/4 wave);   861.7 kHz (3/4 wave);

  Coupled resonant modes:  278.3 kHz and 313.1 kHz;

I reckon that gives a k just under 0.12 and mode 8:9 operation.
The secondary current is pretty uniform, with the top current
coming out at just under 70% of the base current.

  Secondary:
    C_disc:   2.7pF   (in situ)
    C_whip:   4.1pF   (in situ)
    C_coil:   4.4pF   (effective at Fres)
    C_total: 11.2pF   (aka Ces of the resonator)

    Ldc: 28.3 mH
    Les: 26.5 mH      (effective at Fres)

I used a whip length of 0.401m, that's length of whip, not the
height of its top.

I would say we have reasonable agreement with your system, but the
waveforms don't quite match the scope trace in

  http://www.coe.ufrj.br/~acmq/tesla/tefp.html

I have an extra RF cycle in each beat.  Does this graph
represent the system as documented, or was this taken with the
coil base connected to the primary?

Do you have something with which to measure the two actual mode
frequencies to see how close we are?  If so, can you look for the
3/4 wave resonance too and check that?  The 3/4 wave should be at

     primary gap open: 861.7 kHz
  primary gap shorted: 866.6 kHz

That helps to make sure we've got all the dimensions correct.
--
Paul Nicholson
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