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Modeling a magnifier
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From: Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Wednesday, March 11, 1998 5:04 PM
To: Tesla List
Subject: Re: Modeling a magnifier
Hi all,
It is beginning to look as if a number of aspects of
Antonio's modelling is correct.
> From: bmack [SMTP:bmack-at-frontiernet-dot-net]
> Sent: Monday, March 09, 1998 10:30 PM
> To: Tesla List
> Subject: Re: Modeling a magnifier
>
> Antonio,
>
> I think we all agree that there will be a beat frequency with the
> L2C2 and L3C3 connections you proposed. It still seems to me that the
> C2 will be of an impractical size to tune L2c2 near (L2+L3)*c3. I suspect
> an actual system would have large radiation loses in the L2C2 and
> virtually no storage capability in C3. The sparks would be very thin.
> (Ok, I'm guessing here....)
>
> The experiment is flawed if you are using a variable capacitor instead of
> an isotropic capacity as in the real thing. There is no actual ground
> connection as your model posseses. That is what I was trying to say
> in my last post referring to the " out of tune" impedance reflected into
> the primary. With your latest post , i see that you did not use a primary,
> therefore you were unable to see this effect. Check this out on your
> grounded C2 experiment. Replace it with an isotropic capacity of the same
> value, and I'm sure there will be a marked difference in dynamics.
> In my opinion, a model closer to the actual system dynamics
> (simulation-wise) might look more like this:
>
> L2------+----------L3------C3----+
> | C2 Rr
> | Rr |
> | | |
> V V V
>
> The "V" represents ground, Rr is radiation resistance among other
> things
> such as ion channel absorbtion etc. There's been books written on the
> nature
> of Rr...buts thats another topic. At low voltage- very much below
> breakout,
> it's pretty much a radiator. This model will behave as Richard hull
> desribed his results, where C2 is more of a tuning issue for the L1C1
> L2C2 coupled system than it is for the secondary. The Q of the L2C2
> section is impaired by Rr. Depending on the degree that C2 is
> compensated for in the primary, there will be leway for some tuning
> combinations and beats from these interactions.
> For C2<<C3 as in Richard's system, It can be thought of like a
> current
> divider, where the most current will want to follow the (L2+L3)*C3 path.
> Again, the Thumbnail sketch to get in the ballpark is:
>
> L1C1=(L2+L3)*(C2+C3)
>
> As always, comments welcome.
>
> Jim McVey
I ran a well tuned magnifier and examined the waveforms coming off
the secondary in considerable detail. The familiar old beat envelope
associated with the primary/resonator trade is in full swing.
Quenching the gap with no secondary breakout looks to be as far away
as ever. Calculating k off the beat envelope and ring frequency
suggests that Antonio's contention is correct: k for this system
came in at 0.086 compared with k for the driver system alone at >0.4
There was clear evidence of the resonator frequency dominating system
frequency. Primary is tuned to 485kHz. Resonator is at 463.7kHz. Ring
captured on scope is about 465kHz (same as resonator within margin
of error). There is no magical voltage rise when the gap finally
does go out. It looked for all the world like a two coil system.
One of the more interesting waveforms occured when Ep was upped to
allow corona to break out. You could see the resonator ring up with
the usual sinusoidal envelope and then abruptly drop amplitude
somewhat and ring down in linear fashion. Attached sparks caused it
to drop far more abruptly. Attached corona sometimes caused and
exponential decay.
This investigation is acknowledged to be far from complete. For
one thing, primary Q was pretty bad. That will be corrected by oil
filling the driver system (due mainly to corona). A low Xp didn't
help either (14 Ohms).
The main conclusion I drew from this is that mags are a great way
to get the same bang for buck from a much smaller resonator because
clearances between resonator on driving system are no longer an issue.
Malcolm