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Re: Arc length and Gap Dwell Times

Tesla List wrote:
> 
> >From hullr-at-whitlock-dot-comThu Oct 10 22:36:54 1996
> Date: Thu, 10 Oct 1996 10:39:52 -0700
> From: Richard Hull <hullr-at-whitlock-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Arc length and Gap Dwell Times
> 
> Tesla List wrote:
> >
> >
> > The coupling coefficient merely governs how long this process will take,
> > not the portion of energy lost in the transfer process. The longer this
> > takes, the more other losses can reduce the energy left to transfer to
> > the secondary/toroid. The overall transfer efficiencies should be
> > significantly higher with higher coupling coefficients. The above losses
> > provided by Richard are reasonable IF you remove the coupling
> > coefficient as a loss.
> >
> > As usual, flames, brickbats, and rocks are welcomed! :^)
> >
> > -- Bert --
> 
> Bert,
> 
> I must mull this over a bit.  Your argument is compelling.  The coupling
> coefficient is inded the common flux lines of the two coils and the
> multiple feeds of the beats would be the resonant pumping of the
> secondary.  Regardless, if 85% of our flux lines were never common to
> both coils then 85% of the primary lines would never transfer energy.  I
> realize at resonance we are not talking simple transformation.  We are
> still talking energy linkage via magnetic coupling to another coil.  If
> that coil were moved farther away less coupling means grossly reduced
> energy transfer.
> 
>   In resonant systems this may or may not affect the voltage output at
> all!  

Excellent Point! If other losses could be eliminated, one should get the
_same_ output voltage on a given secondary/toroid system even as the
coupling coefficient is reduced. It would just take longer. I would
slightly ammend your statement above to read "If that coil were moved
further away less coupling means grossly reduced energy transfer _per
resonant cycle_". 

> When over couplied, with a given gap system, a reduction in
> coupling will actually increase spark length dramatically! (increase
> output voltage.)  The energy transferred has decreased severely, but the
> performance, or spark output, has increased dramatically.  The losses due
> to magnetic coupling in our air core systems far exceeds all the total
> losses of all the other agents combined.

I suspect that this is mainly due to the extreme difficulty in
preventing the gap from reigniting at higher coupling coefficients,
since the secondary energy wants to more rapidly transfer back to the
primary. As you are painfully aware, this often requires heroic efforts!
However, if one were able to achieve perfect quenching, and could ignore
other primary losses, the total energy transferred to the secondary
should be the same but just take longer (more "pumps").  

> I have had my doubts about the Corums and the 1/2 cycle theory for some
> time.  I hope to do the H2 thyratron testing soon and varying the dwell
> to a moderate powered system over a long range and see how it affects the
> spark to hopefully agree or disagree with the theoretical approaches.
> Naturally I hope to vary the coupling range of the systems independently
> at the same time.
> 
> Good post and more stuff to digest.
> 
> Richard Hull, TCBOR

Thanks! Its clear you've spent a lot of time thinking about this! Based
upon Dave Huffman's latest simulations, the Corum's energy fall-off
chart appears to be overly pessimistic for quench-times below the 1/2
beat "optimum". I'm also starting to believe that the "magic" coupling
coefficients (0.28, 0.22, 0.18, 0.153...) may not be _quite_  right,
since the primary's coupled excitation frequency will normally be
different than the uncoupled center frequency. More
thinking/measurements are needed here. This also may be a case where
existing simulation tools fail us...

I'm very much looking forward to the empirical results you obtain with
precision quenching and some of the future work Malcolm is planning!

Safe coilin' to you, Richard!

-- Bert --