Re: Optimum toroid size

["Barton B. Anderson" <tesla123-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Gary,

I think many of us would tend to agree with you here. But for the purpose that
John C. and others are looking at, ROC plays a significant role. Wouldn't it be
nice define and build a toroid that would pull a single streamer without the
breakout point? Obvioudly a smooth toroid is critical in the construction. But,
we are a long ways from being able to do this on paper. I'm glad some of the
list members are looking into this. In my opinion, this has been and still is
one of the major problems when designing a coil. We are still left to trial and
error with a little help from experience.

Regardless, I think ROC plays a significant role even with a breakout point
mainly because ROC is typically associated with size and therefore top C. The
small ROC (breakout) is significant regarding streamer voltage. I look at it as
a fine adjustment for the top load streamer voltage that "doesn't affect top C
or the efield" as does the ROC and size of the actual toroid. A very useful
little bump.

Take care,
Bart

Tesla list wrote:

> Original poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
>
> The discussion so far has been how to maximize top-load voltage prior to
> breakout.  Increasing top-load size results in higher radius of curvature
> (ROC), which increases breakout voltage, while increasing top-load size also
> decreases maximum attainable secondary voltage by virtue of conservation of
> energy Esec (0.5 CpriVpri**2) <= Epri(0.5CsecVsec**2).
>
> I have to wonder though whether maximizing pre-breakout top-load voltage is
> a necessary condition for optimum performance.  Many, if not most of us use
> a breakout point on our top-loads.  They serve to direct the streamers to
> where we want them, force breakout to occur, and also to concentrate all
> available energy into (hopefully) one long streamer.  But it would seem that
> the use of breakout points renders the ROC consideration a mute point.
>
> If I have a toroid with a breakout point and streamers don't occur, then I
> conclude that the top-load capacitance is too large.  If I have a toroid
> with a breakout point and *multiple* streamers occur (I want only one), then
> I conclude the top-load capacitance is too small.  But I don't believe ROC
> of the top-load is a major consideration.  Is this thinking incorrect?
>
> Gary Lau
> Waltham, MA USA