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Re: Corum's Resonator Theory
From: DR.RESONANCE[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Thursday, October 30, 1997 10:35 PM
To: Tesla List
Subject: Re: Corum's Resonator Theory
to: Malcolm
Don't buy all of it. If your sec coil is setting atop a 24 inch high base
(as an example) the primary magnetic field will sweep upwards and downwards
essentially equally. If the base is setting on a concrete floor or outside
on the ground this means your sec coil could only be a max of 24 inches
high because the downward sweep would short out in the ground plane. I
still feel a lot of the energy is coupled in the lower end of the sec and
propagated as a wave motion rather than an entire coupling of the sec coil
by the primary coil. Your experiments are neat and hopefully will provide
some interesting answers to these questions.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Corum's Resonator Theory
> Date: Thursday,October 30,1997 6:28 PM
>
>
> From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
> Sent: Thursday, October 30, 1997 6:03 PM
> To: tesla-at-pupman-dot-com
> Subject: Corum's Resonator Theory
>
> Hello All,
> After some cogitating and some discussion with Kenneth
> Corum, I now understand where they are coming from when comparing
> lumped vs distributed theory. Before I launch into this, please note
> that (a) I am assuming *no* topload for the resonator, and (b) no
> spark is issued from the resonator under any conditions (see
> "problems" below). Assuming these two points, here are the basic
> ideas:
>
> (1) The claim is made that in the two-coil system while the primary
> is coupled to the secondary (spark gap conducting), the resonator
> current is uniform (i.e. current is the same at every point along the
> resonator). Now I am at a loss to see how that can be given (a) that
> the coupling to the primary is vastly lower at the top than the
> bottom, and (b), in a resonator without topload, how a current equal
> to base current can be present in the top turns. Let's suppose anyway.
> Suppose the current is uniform. Then the voltage increase along
> the resonator is a linear one i.e. voltage linearly increases from
> bottom to top while the current is the same. That voltage gradient is
> entirely reasonable if one considers that a current through a portion
> of L generates a voltage across that L. In this situation, it is clear
> that energy is evenly distributed throughout the resonator (according
> to E = 0.5Li^2 where one considers the resonator to be devoid of any
> self capacitance. Unfortunately it does have capacitance distributed
> along its length. Exactly how that capacitance is distributed is a
> matter of contention. However, the Corums are modelling the resonator
> as a uniform line so let us suppose that it consists of equal L and C
> sections. Now it is clear that energy under conditions of uniform
> current must be lumped towards the top end because one can sum Li^2
> and CV^2 for each portion and the sums are different if one considers
> the bottom vs the top. Hence, one can say that for this model under
> coupled conditions, energy is not evenly distributed *even if the
> current is uniform*.
> It seems to me to be highly important now that the actual current
> distribution under coupled conditions is definitively measured for
> once and for all to establish the truth of this picture. Ken Corum
> tells me that one should disregard the uneven coupling and simply
> think about the resonator as being very much shorter than the
> wavelength so all portions of the resonator are immersed in the
> primary field - hence the uniform current. Anyone here buy that
> argument? Anyone here measured current in different portions of the
> resonator when it is coupled to the primary?
>
> (2) Now we go from the coupled to non-coupled situation. Here is what
> they are saying happens (and why the resonator differs from a lumped
> circuit). The spark goes out, and at the instant it does so, the V-I
> distribution as outlined above is present. Suddenly the resonator is
> no longer gripped by the primary. Now, *supposing* that the current
> *was* uniform, what happens next? Well, the idea is that over some
> period of time depending on the propagation delay along the length of
> the resonator, the current *now* becomes NON-UNIFORM. That is, it now
> assumes a maximum at the base and a minimum at the top. If it does so
> re-arrange itself, what happens to the voltage distribution? Now if
> we look at the Ldi/dt scenario, most of the voltage rise will be in
> the bottom turns with virtually none at the top. In other words, the
> rise going up from the base is huge and tapers off as one reaches the
> top. Energy has now evened itself out over the resonator length, at
> least that is the picture I get. Voltage distribution is no longer
> linear but is now sinsoidal. But we still have the same total energy
> in the resonator.
>
> I would be obliged to the mathematicians among us if they could
> quantify how voltage at the top might now be different under these
> conditions.
>
> Problems as I see them:
>
> (1) I don't think anyone has actually measured current distribution
> under coupled conditions (or have they?). Please let us know if so.
> It is crucial to this model to know whether k influences current
> in different portions of the resonator or not. It is also crucial
> to know whether one really can have as much current in the top turns
> *even with what capacitive loading there is*. Mr Corum dismissed the
> coupling argument and ignored the second despite being asked twice.
> We do *know* that k is an order of magnitude less between the primary
> an top turns and the primary and bottom turns in general terms.
>
> (2) No breakout under these conditions is a total piece of fiction
> when it comes to practice IMHO. Is MHO wrong? Anyone ever prevented
> breakout from a piece of wire at XXX,000 Volts?
>
> (3) The re-arrangement of current (which it is claimed would result
> in a voltage rise over the lumped situation) has not been observed by
> anyone I know. Personally I have captured waveforms using a
> storage scope many, many times and not once have I ever seen a
> hint of this, breakout conditions or no. In fact, I will touch on
> this problem in point (4) below. Perhaps someone has seen it.
> If so, please, please post.
>
> (4) As most will be aware, trying to quench a gap under no breakout
> conditions is a notoriously difficult exercise. However, the
> implication is that a voltage rise should be observed *any time* the
> gap is quenched, no matter how little energy remains as long as it is
> not zero. Once again, has anyone ever seen it?
>
> According to Mr Corum, it is this extra rise that is the secret
> of a "true" Tesla Coil. I repeatedly queried him on quench issues and
> came up against a brick wall in trying to extract an answer. How many
> people who have examined coil waveforms in minute detail believe that
> you can cut a gap off when all the energy remains bottled up in the
> system (e.g. ideal first notch quench without discharge)? If Mr C's
> theory is correct and this can be done, then I think we are in for a
> treat. If not...... None of my coils have ever done it including the
> one with the difficult-to-break-out-of topload I posted on in the
> last couple of days. In attempting to do this, I blew a *jet* of
> compressed air through the gap. No voltage rise was observed on the
> scope from the time the gap was cutoff and to make matters worse, the
> gap losses roughly doubled according to both a discharge test and
> the scope not to mention the gap flame and noise.
>
> If anyone has observations, measurements, comments etc. I for one
> would love to hear them. This post is done as much to advance my own
> understanding as it is an attempt to clarify the issues. I would just
> like to observe two things - the distributed model fails to predict
> the resonant frequency if one uses lumped L and lumped C, and from
> the diagrams I have seen in the Corum's papers, they are considering
> a *balanced* line as a model. Does that make any difference? (I plead
> with those into scalar theory not to make an issue of this). Mr Corum
> states that Maxwell and other conventional engineering theory are all
> that is needed to predict resonator behaviour.
>
> Thanks for listening,
> Malcolm
>
>