[Prev][Next][Index][Thread]

RE: Redistribution of secondary voltage

Hi Will,

> Original Poster: "Payne, Will E" <will.e.payne-at-lmco-dot-com> 
> 
> Malcom,
> 
>    Dare a novice yet again show my opinion to a veteran ?  You bet !

Goforit!! :)
 
>    It occurrs to me my earlier comments on the mathematical plausibility of
> redistribution of secondary voltage would be valid only under extreme close
> coupling and very sharp excitation.  That is, the excitation pulse width is
> much less than 1/fo.  It is valid as a mathematical concept and likely it
> could be produced in the lab, but I doubt it would happen in any TC such as
> I have ever seen.

Exactly! I said as much in a reply I posted just moments ago. Agree 
wit your analysis 100%. In fact such a pulse is extremely broadband 
spectrally.

>    If you really think its happening, instrument an unloaded resonator with
> a current probe near the top, and look for a fall in current as the energy
> redistributes itself.

Terry would be well placed to do such a test with his 
instrumentation. BTW, the postulated uniformity of resonator current 
under coupled conditions with no topload should be tested as well so 
that unsound (IMHO) bogey can be put to bed one way or the other as 
well.

Cheers,
Malcolm

 > Makin' lil bitty sparks in Georgia
> 
> Will
> 
> ps does "redistribution" = "coherence" ?
> 
> >       My understanding: the argument is made by them that during 
> > ringup (or resonator fill?), the resonator behaves as a lumped 
> > circuit exhibiting a uniform current throughout its windings (how it 
> > could possibly be identical at the top and bottom with no topload is 
> > beyond me). They argued (in the notes) that this uniformity was due to
> > the primary coupling to the entire resonator. Well it does - sort of.
> > k at the top as we all know is a tiny fraction of what it is at the 
> > bottom if one measures it. However, they then say that once the energy 
> > is trapped therein by primary gap quench, over a period of time 
> > (coherence time) the current changes from being uniform to being a 
> > maximum at the base and minimum at the top. As a result, voltage 
> > gradient across the windings also changes from being linear (I x Xl) 
> > to assuming a non-linear gradient (sinusiodal presumably). The 
> > voltage is always going to be ideally zero at the bottom in the two 
> > coil system so that doesn't change but what does (they say) is the
> > volts/turn across different portions of the winding. The difference 
> > in total output voltage is claimed to be VSWR vs Q (i.e. rises to 
> > about 1.3x the fully rung-up value). That's how it reads to me anyway 
> > and whatever the final value is claimed to be, Ken C. reinforced this 
> > view in some email to me. It is this redistributed voltage rise that 
> > I have been looking for and failed to find. He claims it is easy to 
> > see. I never have. Perhaps I have it all wrong but the implication to 
> > me is that if the system quenches at the end of the second ringup and
> > system losses are low enough, voltage some time down the track 
> > (Tcohere) will rise to a value that might exceed the value it reached 
> > at the end of the first ringup. Perhaps somebody can throw some light 
> > on this. I've never seen any rise beyond natural ringup rise in 
> > dozens of tests. They claim it happens in the normal course of events 
> > in a standard two-coil system after gap quench.
> >      If anyone knows of an experimental setup that would allow this 
> > to be seen, I would be most grateful to hear from you.
> > 
> > Regards,
> > Malcolm