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RE: 180 BPS synch? (fwd)

---------- Forwarded message ----------
Date: Fri, 13 Jul 2007 11:17:20 -0700 (PDT)
From: J. Aaron Holmes <jaholmes@xxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: 180 BPS synch? (fwd)

...but what a squandered opportunity to dust off the
trig functions on your calculator and play with some
coil formulas!  Oh well...

So, 180 bps is 120 degrees between bangs, and 120 bps
is 180 degrees between bangs.  How handily confusing!

Not showing all my work:  If you pretend you have a 2F
capacitor and a 1V (peak) transformer, then the energy
per "bang" is just sin(t)^2 where "t" is the phase
angle of the "bang".  Energy per cycle at 180 bps
would therefore be:  sin(t)^2 + sin(t+120)^2 +
sin(t+240)^2, where "t" is the phase angle of the
first "bang" in the AC cycle.  Pick a few values for
"t", and you'll see that your energy per cycle always
see mes to come out to 1.5J.

Energy per cycle at 120 bps would be:  sin(t)^2 +
sin(t+180)^2 (again, where "t" is the phase angle of
the first "bang").  If "t" is 90 degrees (the AC
peak), then your energy per cycle is 2J.

...which is "better" than 1.5J :-)

Since power is energy per time, and there are the same
number of AC cycles per second regardless of your
break rate, then the ratio of the energies above is
the same as the ratio of the powers.  Hence, 180 bps
only gives you 75% of the power that a properly-phased
120 bps would give you, assuming all other
characteristics of your coil are equal.

Of course, perhaps there is some bizarre correlation
of break rate to spark length in here that might
somewhat make up for the lower power, I don't know.  I
haven't followed the streamer modeling discussions as
much as I probably ought to have.  If any such bps
advantage existed, the question would then be:  Could
it make up for a 25% power shortfall?  The answer: 
Probably not.

Aaron, N7OE

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> ---------- Forwarded message ----------
> Date: Thu, 12 Jul 2007 21:19:19 -0400
> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: RE: 180 BPS synch?
> Nobody responded to my message (not even a "yes,
> it's been done" or a "no it 
> won't work"), so I'm reposting it on the assumption
> either nobody got it, or 
> nobody took the time to read it and respond, thanks.
> Scott Bogard.
> >From: "Tesla list" <tesla@xxxxxxxxxx>
> >To: tesla@xxxxxxxxxx
> >Subject: 180 BPS synch? (fwd)
> >Date: Mon, 9 Jul 2007 15:05:02 -0600 (MDT)
> >
> >
> >---------- Forwarded message ----------
> >Date: Mon, 09 Jul 2007 16:31:13 -0400
> >From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> >To: tesla@xxxxxxxxxx
> >Subject: 180 BPS synch?
> >
> >Greetings all,
> >      I was curious, what would the results be of a
> synchronous motor (1800
> >rpm) being used with 6 electrodes, for 180 BPS.  My
> thinking is that the 
> >arc
> >put out would be slightly more random due to uneven
> firing voltages, like 
> >an
> >asynch gap, but prevent dangerous resonant rises,
> due top it's tenancy to
> >inevitably repeat a defined patter over and over
> again (also different
> >"phasing" may effect output, but I don't think it
> would ever settle on a
> >phase it cannot operate with, or one that would
> give optimum power).  Has
> >anybody tried this, what do you guys think (I just
> finished building a
> >120/240 BPS sync, so I don't think I will be
> building another soon, but
> >maybe somebody else can try it).  Thanks.
> >Scott Bogard.
> >
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