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Re: Top Toroid

> The other problem with excessive dwell times is that the energy that's
>transferred to the secondary/toroid couples back into the primary
> circuit, to be dissipated as heat. This problem becomes even worse if we
>don't have heavy secondary streamers "helping" to reduce the secondary
> energy coming back into the primary circuit. 

This is something that I had read about, then you mentioned it a number of
times, but I tend to still forget it--must be the onset of early senility on
my part!  Thanks for having the patience and/or persistance to reiterate.
 
> Robert Stephens showed me a very interesting videotape of his large
> disruptive system where the toroid was intermittently breaking out.
> During the times he had no breakout, the light intensity coming from the
> rotary was MUCH brighter than when he was getting good streamers. Lots
> more energy was clearly being dissipated in the gap, and I have no doubt
> a lot more heat production and electrode erosion were occurring as well. 
 
It's nice to be able to see these effects in the real world as seen above!

> John, your thoughts regarding slower versus faster break rates may be
> true. However, I would also propose that its more important to have the
> minimum amount of dwell time (through offset electrodes for example) so
> that we will complete the first full primary-to-secondary energy
> transfer, but quench before transferring any back. This should also be
> the most efficient operation as referenced from the input power mains.
 
I agree that the main thing is have a short dwell time and to quench quickly,
my thoughts about the slow break rate are, I agree, a more minor
consideration that I just threw in as possibly having at least a theoretical
advantage.  And of course, I use a high rotor RPM, even with low break-rates
to help to "stretch" the spark and quench it.  I must admit that the low
break-rate may have no advantage since it will then need a bigger cap, bigger
bangs, = more heat per bang, with the result that it may all even out "in the
wash".
  
>Assuming we have proper dwell, we can increase the break-rate (and
> assuming that we can recharge the tank cap quickly enough), get more
> overall power transferred to the secondary. [This implies that we may
> want to use a larger tank cap and fire the gap at a lower voltage so as
>to get the same energy per bang, and more bangs per AC half-cycle]. Once
>we start breaking out, more power delivered to the secondary should
>result in more energy going into the longer, and hotter streamers, and
>less proportionately being dissipated in the gaps. 

I think the question then is; will the greater gap cooling time that exists
with slow break-rates "overwhelm" the greater power that will be dissipated
due to the larger cap.  In other words, will the gap run cooler and quench
better with a few big bangs and a long cooling time, or will it run cooler
and quench better with more small bangs but less cooling time.  Is there a
non-linearity to one of these aspects as compared to the other, which may
give a benefit?  Or it may be equal, or so close to equal that it doesn't
matter?  It is probable, I would think, that for a maximum power TC, one
would want to use a high break-rate, and everything else "high" too; large
cap, and high voltage!  But few of us have the power source and space for
such a system. 
 
> I'd even contend that an "ideal" asynchronous system (other than a
> DC/charging choke system) might employ a very rapid rotary (assuming
> adequate dwelltimes). The ballast characteristics and voltage-point of
> the incoming AC waveform will govern how quickly the tank cap will be
>recharged. If we size these properly, they, and not the rotary, will
>govern how many times per half cycle we actually fire, and these could
>be adjusted to limit the actual breakrate to below 600 BPS. By using a
> high rotary speed, we'd always have another electrode presentation
>within a relatively short period of time, so that if we "just miss" one,
> we'll hit the next very quickly, minimizing jitter. A static gap, set at
>a slightly higher breakover voltage, shunted across the rotary could
 >also be used to handle "misses". 

This could be done, but it seems like what would happen is that the
presentations that are low on the AC power sinewave are the ones that would
be missed, and we may fire only at the AC peaks.  If we raise our voltage to
the lower presentations are not missed, then it seems unlikely that the ones
at a higher point on the sine wave will be missed--or am I missing something?
 Also if a firing is missed, the next one would be extra strong probably (due
to more cap charging time) , which may be good or bad.  Maybe the "unequal"
gap spacing technique would be useful to equalize the firing voltage.

In a related experiment, which may have some bearing on the above, when I
built my DC compound storage disruptive staccato TC, (the one in the TCBA
article), it sometimes missed a firing of the enabling gap.  When this
happened, the next firing was extra strong since the filter/storage cap
charged up longer.  This sometimes caused racing sparks, since the gaps had a
harder time quenching, since more energy was supplied.  Sometimes the
sync-gap would throw metal out, if the chokes that controlled the
filter/storage cap weren't of the correct value.

I suppose in the "static gap for handling misses" concept, the gap would have
to be an excellent quenching gap with many gaps and a giant blower to quench
properlly and not contribute to the racing sparks that we're trying to avoid.
 But the static gap may eliminate or reduce the problem of jitter and cap
"overcharging".  It may be difficult to find a proper spacing of the static
gap that would make it work correctly.  But it's an interesting concept that
I never thought of.

It is still a question in my mind, whether slow break-rate, big bang, is
equal to fast break-rate, small bang.  There could be something going on
with, for instance, the ion cloud that cause sparks to "grow" better with one
scenario than with the other.  Something perhaps related to Richard Hull's
findings, that slow break rates cause more DC electrostatic charging, (and
maybe more spark length too)?  This whole break-rate question seems
underexplored compared to many other TC aspects.

Going back to non-sync gaps, I had an idea, which I don't know if I posted
previously, that may suggest a scenario whereby non-sync gaps may enjoy an
unexpected boost in efficiency:  When a non-sync gap is run at a certain
speed, and with a certain number of electrodes, it may give for instance 2
breaks per half cycle for awhile, then 3 breaks per half cycle, for awhile.
 In this cycling is rapid enough, the eye will not really see the sparks
cycling (varying) in length, yet strong sparks will occur on a
regular,periodic basis, sparks that are perhaps longer than what would be
expected at the AVERAGE power level being used.  In other words, some sparks
are strong, some are weak, and the average power input is somewhere "in
between", so current is lower (than if all half cyles had 3 breaks), yet we
do occasionally get strong sparks, which is all we really care about.  And we
can declare now declare this coil "more efficicient", from a "coiler's"
viewpoint, but not of course from the true engineering viewpoint.

>Flames, brickbats, and cat-calls are heartily welcomed. :^
 
>- Bert H. --
  >>

Guess I carried on enough for today!   Comments (of all types) welcomed!

John Freau