Fw: Re: A further belated s.s. realization

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Original poster: "K. C. Herrick by way of Terry Fritz <teslalist-at-qwest-dot-net>" <kchdlh-at-juno-dot-com>

Well, now I'm backtracking again.  Further cogitation leads me to believe
I may not have a problem after all.  Referring to the prianal.gif drawing
referred to below (and that's "anal" not as in -retentive but as in
analysis), I'd neglected to consider, or show, that each pair of
"inductors" that is on a radius (actually the dual segments of the
primary "coil") exhibits 1:1 transformer action because of the close
proximity of the two conductors.  That means that any differential
voltage tending to appear at one end of the pair will tend to be
generated at the other end.  And conversely, any impediment to such a
voltage at one end will appear at the other.

Thus in the #2 circuit of the upper pair, for instance, the tendency of a
coupling capacitor's charge to change during the crossover-time, due to a
resonance condition, will be reduced by the presence of the electrolytic
capacitor at the other two terminals of the "transformer".  That makes
both of the circuits #2 close to the same in their action.

Furthermore, the "no good" scheme may actually be the better one.  As
soon as the condition of the #2 circuit obtains, the primary loop finds
that, instead of incorporating 4 electrolytic capacitors whose charges
have been making that loop's current increase, there are now the other 4
in the circuit but connected in the opposite polarity, so the current
will very rapidly decrease toward zero--at which time the transistors
paralleling the then-conducting diodes, already turned on for the next
half-cycle of operation, will take up the current.

Make sense, anyone?  I'm working on simulating it with SIMetrix.

Ken Herrick

--------- Forwarded message ----------
From: K. C. Herrick <kchdlh-at-juno-dot-com>
To: tesla-at-pupman-dot-com
Date: Fri, 7 Mar 2003 14:57:22 -0800
Subject: Re: A belated s.s. realization

Hold on just a minute...

Still having concerns, I made up a drawing comparing my original scheme
with what I've started on as a re-design.  See
http://hot-streamer/temp/prianal.gif.  The drawing shows current flows
for 1/2 cycle of primary excitation.   The circuits do not show the
several primary turns I actually employ but the principle is the same.

Looking at the '"original scheme" circuits, you can see that, during the
transition time when all switches (i.e., transistors) are open (the ckt
to the upper right), inductive-kick current passes through each pair of
low-capacitance coupling capacitors and through fast diodes, clamping the
voltage across the just-turned-off transistors to twice the
electrolytic-capacitor voltage.  At the instant that happens, a resonant
circuit appears consisting of all the presently-conducting inductors (the
primary turns) and all the coupling capacitors.  If the coupling
capacitors have sufficiently low capacitances, the Fr of that circuit at
that time is sufficiently high so that the next zero-crossing of that
current occurs only a modest fraction of time into the next 1/2 cycle of
the transistor excitation (which is at the secondary's Fr).

At that time, the alternate transistors start to conduct (the ones across
the just-finished-conducting diodes) and current starts to flow through
them and the alternate set of inductors (the 2nd set of primary
conductors) in the opposite direction.  The cycle repeats for the
duration of the spark event.

But look at the "N. G." scheme:  Here, it had occurred to me that I might
combine the energy-storage capacitors with the coupling capacitors; make
them one & the same, so to speak.  That's what the drawing shows.  But a
look at the right-hand ckt shows that the Fr during the transition time
is now determined not by small-value coupling capacitors but rather by
large-value electrolytics.  Thus, it will take a very long time, relative
to a secondary-Fr half-cycle, for the "catch"-diodes to quit conducting.
Like, perhaps 1000 times longer.  That is definitely no good: the
alternate transistors will never conduct.

So...does anyone have a comment on this while I go back to the drawing
board?

Ken Herrick

On Thu, 06 Mar 2003 20:09:50 -0700 "Tesla list" <tesla-at-pupman-dot-com>
writes:
 > Original poster: "K. C. Herrick by way of Terry Fritz
 > <teslalist-at-qwest-dot-net>" <kchdlh-at-juno-dot-com>
 >
 > Yeah, I was suffering from a temporary anxiety attack.  As I now
 > realize
 > I'd figured out long ago, my catch-diodes will just do their thing,
 > and
 > when they're finished catching, then the transistors will take
 > over.
 >
 > Ken
 >
 > On Wed, 05 Mar 2003 20:08:05 -0700 "Tesla list" <tesla-at-pupman-dot-com>
 > writes:
 >  > Original poster: "jimmy hynes by way of Terry Fritz
 >  > <teslalist-at-qwest-dot-net>" <chunkyboy86-at-yahoo-dot-com>
 >  >
 >  >
 >  > Hi Ken,
 >  >
 >  > This happens in h-bridge and half bridge circuits too, and is
 > easier
 >  > to
 >  > visualize...

[snipped]