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Re: Optimal Quenching Tests
>John,
> Because the spectral splitting does _not_ occur during the time the gap
>initially ignites and the first primary notch! Believe it or not, ever
>since (October) I found out about this phenomenon, I've been thinking
>about why... ya' know, one of those things that make you go hmmmm....?
> However, I think I understand at least part of it. Some speculation:
> 1. The secondary usually has a much higher Q than the primary. During
> the first ring-up, the secondary will actually "pull" a mistuned
>primary's frequency to the secondary circuits resonant frequency Fs.
>(This is handy for when we run primary frequency a bit lower than Fs for
>ion-cloud compensation).
>2. During secondary ring-up (but before breakout), the secondary "looks"
>like a series LC at resonance, i.e., the reactances cancel, and it
>appears like a resistive load. Hence no splitting during the first
>ring-up.
> 3. This resistive load gets coupled back into the primary as a resistive
> load (other than the fact it can "pull" the primary frequency to Fs). In
>effect, during ring-up, the energy transfer is one-way from primary to
> secondary, into a resistive load, hence no split. The primary is dumoing
> energy into the "black hole" of the secondary tank circuit, and not
>getting any back (yet).
> 4. The first primary notch comes from the fact that, eventually, we run
>out of primary energy (i.e., finite "bang" size). At this point, all the
>remaining system energy now resides in the secondary LC, just itching to
>couple back into the primary if we let it.
Bert,
Thanks for the speculations, and thanks also for the info in your other post
answering my Q measuring questions. I've been doing some speculating also:
1) Are the PSPICE conclusions really refering to splitting, could they be
refering to beating? Splitting can eventually lead to beating. I can see
how 1st notch quench would eliminate beating because the primary would
contain only 1/2 of a beat period, and the secondary would also contain 1/2
of a beat period. I agree that for beating to occur, energy must make a
round trip, as you said, energy flows only one way if we quench at first
notch--therefore no beating. But I think we still get splitting. I don't
know if this splitting can cause racing sparks.
2) Did the old spark transmitter engineers really say that 1st notch quench
eliminated splitting, or did they say it eliminated beating? Maybe they just
looked at their secondary waveform and said, " look, a nice clean
ringdown....no beats....just what we want!" Also, in Richard Hull's
comments on the subject, was he refering to splitting, or to beating? Are
we differing on our definitions of terms?
3) I agree that a key point is the one way transfer of energy from the pri.
to the sec., Once the energy makes round trips, undesirable phase shifts and
beating wreak havoc by creating unwanted frequencies, which result in racing
sparks.
4) I think the first notch is caused by the additive effect of the two split
frequencies; at the point when they are 180 % out of phase--they cancel and
cause the notch. Also, since the energy in the secondary is out of phase
with the primary, the secondary is now at it's maximum energy level.
> haven't taken the speculation past this point... However, "classical
>theory", observation, and PSPICE all show that frequency splitting will
>occur beyond this point (once energy flow reverses).
Again, I think splitting always occurs in an over-coupled, double-tuned
circuit, but beating can be eliminated by quenching at the first notch.
>Flames, brickbats, etc. are welcomed!
>-- Bert --
>>
Are we "splitting hairs", and "beating" our brains? All comments are
welcomed.
John Freau