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Re: How to rise the secondary? (fwd)



---------- Forwarded message ----------
Date: Sat, 18 Jul 1998 17:51:22 -0600
From: terryf-at-verinet-dot-com
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: How to rise the secondary? (fwd)

As a computer experiment, I tried a series of couplings with my best model
of my coil, just to see what it suggested.  These are without streamer
loading.  The results are as follows:

Coupling        Peak voltage
0.05            191 kV
0.10            333
0.15            419
0.20            439
0.25            455
0.30            473
0.35            474
0.40            493 (sweet spot)

Above this, there are good and bad points.  The waveforms get very funny
looking at high couplings.  If we could quench on one of the peaks, it would
be great but that is far beyond any known gap's performance.  The
theoretical maximum voltage is (SQRT(Cp/Cs)Vi) is 545 kV with no loss.
Perhaps there is a coupling point that could transfer the energy to the
secondary before the losses chew up the energy but you could never quench on
or couple that k value without arc over.

If you can couple at 0.15 or above and still get a first notch quench, you
are doing pretty good.  Below 0.15 you may be loosing performance.  

        Terry Fritz





At 01:50 PM 7/18/98 -0600, you wrote:
>
>
>---------- Forwarded message ----------
>Date: Sat, 18 Jul 1998 10:00:03 -0500
>From: "Barton B. Anderson" <mopar-at-uswest-dot-net>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Re: How to rise the secondary? (fwd)
>
>John, all,
>Coupling is two-fold. First, coupling is a coefficient of magnetic flux linking
>inductors resulting in some amount of energy transfered.
>
>Secondly, coupling should also be realized as a very real physical energy
transfer.
>What is it were coupling? Well, a voltage potential producing current in
the primary
>causing a magnetic field to be generated thus coupling the secondary.
Remember, it
>is a magnetic field we are coupling, and magnetic fields move in "size and
density"
>*with and by* the AC component (em field).
>
>An em field produced in the primary will have a varying size , position, and
>density. Current determines these parameters of the em field once the
primary and
>secondary are in place, and quenching determines the amount of current
transferred
>per time.
>
>By *theory*, if we are "over-coupled" (too close, too much current, large
em field),
>the em field flux lines of force "does not" engage optimally and there is less
>energy transfered than what could be. If we are "under-coupled" (too far
away, not
>enough current, small em field), the em field flux lines of force "does
not" engage
>optimally and again there is less energy transfered than what could be.
>
>With TC's, I theorize that regardless of under of over coupled conditions,
distance
>of Pri to Sec arcing is set to prevent a *voltage* determined occurance.
This does
>not mean we are favorably coupled. It only means the Pri is far enough away
from the
>Sec to prevent arcing based on *current* and *quenching* conditions.
Raising and
>lowering the secondary *does* change the coupling due to the positioning
within the
>em field.
>
>It is very possible, that due to the voltage level on the primary, our
maximum and
>most efficient K is beyond our reach with present design. Because quenching
(energy
>transfer) changes the current/time occurrance, it also changes the em field
and flux
>density. This may explain racing sparks along the secondary at low power
levels vs.
>high power levels and why changing the secondary vertical positioning can
elliminate
>or minimize this condition and produce sometimes longer, sometimes shorter arc
>length.
>
>Until a program can take into account the em field parameters (sparkgap
quenching,
>current/time, etc..), coupling is a hit and miss condition. With a system
designed
>to just beyond the Pri to Sec arc distance, raising the secondary *can*
provide a
>better *coupling*, it may also reduce coupling depending on the em fields
>relationship to the secondary.
>
>At some point in our TC technology, we must begin research to best shape the em
>field. This is where programs such as SPICE will play a large roll.
>
>Sorry to respond so late to your first post. My life got real busy here
lately. BTW,
>I did review all the other posts.
>
>Take care,
>Bart
>
>Tesla List wrote:
>
SNIP