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magnifier vs. classic tc (magnifier modeling)


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From:  FutureT [SMTP:FutureT-at-aol-dot-com]
Sent:  Monday, March 23, 1998 8:12 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: magnifier vs. classic tc (magnifier modeling)

In a message dated 98-03-23 01:46:45 EST, you write:
>>snip
<< > I can see strong beating effects in the after-quench ringdown
> > waveform on the scope.  This beating changes drastically as I
> > adjust the variable tune cap. The beat period can be made long or short,
> > by adjustment of the tune cap.
 
> This is expected. The voltage at the top of the third coil always
> shall present beats (if C2 is significant), with variated appearance and
> generally mixed with higher-order resonances, what can turn the 
> observation difficult (how are you observing the waveforms?).

Antonio, all,

I'm using a short piece of wire at the end of a shielded cable, placed
about 2 ft. from the top of the resonator.  The driver is about 3 ft 
further away.  The cable connects to a regular (non-storage)  
oscilloscope. 
>
>> snip
> > In one case, the RF formed what looked like a beat that was
> > 34uS long which would imply an effective k = .06.  Calc. is about
> > k = .14.  In still another test, the beat period seemed to be 24uS,
> > but in both cases, there were visible beats within the main beats.
> > So the effective k depends on which beats you look at. 
 
> This is before or after quenching? With significant C2 the system
> oscillates at three different frequencies, not counting harmonics,
> and the waveforms become very confuse before quenching. I don't
> know what would be the ideal tuning before quenching. Probably
> some condition resulting in long beats at the primary circuit, if
> possible.

This is before the quench, sorry, forgot to mention that.
 
> > snip   >   When the
> > point is installed on the toroid, then the RF rings down lower and
> > lower as each beat occurs.  But when the point is not installed, the
> > RF rings up over a number of beats, then down over a number of
> > beats.  This is what gives the appearance of one long modulated
> > beat (and there are a number of these large ones too, these long
> > beats ring only down from beat to beat, never up).
 
> After or before quenching? An increase of beat amplitude after the
> quenching is something unexpected.

Again, this is before the quench.
  
> > I also tried tuning the primary at turn # 20, results were a little
> > different, but I have to recheck this.  The only other tune point I
> > tried was around turn # 24, but no sparks were obtained.  The
> > variable tune cap doesn't seem to affect the overall frequency very
> > much.  But tuning of the variable cap was very critical in all these
> > tests.  I didn't recheck to verify that Fo was somewhere around
> > 500kHz.
 
> This is expected. But C2 controls how much of the primary energy goes
> to the secondary end, and how this energy is transferred to C3.
  
> > Some variable cap adjustments resulted in a modulated appearance
> > in the sense that two beats would be strong, then two were weak,
 >> then two were of intermediate height, then two were weaker yet, etc.
 
> Expected, from the combination of three sinusoids at different
> frequencies.
  
> > I also ran the coil without the variable tune cap, and I can see that
> > the beats *are* occuring after the quench even with the small self C
> > of the secondary (or it certainly looked that way).  The spark output
> > is a little weaker without the variable cap, but tuning is probably not
> > as precise.  Without the variable cap, the beats were about 10uS.
 
> Expected. But as I said above, the voltage at the top terminal (C3) is
> very complicated due to high-order resonances. Verify what happens at
> the top of L2.
  
> > I may try using the 5.75mH secondary coil, but oil breakdown may
> > occur in the variable cap.
> > More work is needed.
 
> Ok. Going step by step, I believe that an accurate figure of what the
> magnifier does can be derived.

Agreed.  I'll try to look at the things you mentioned.

John Freau
 
> Antonio Carlos M. de Queiroz
> http://www.coe.ufrj.br/~acmq
  >>