Re: TC Electrostatics (fwd)

To: tesla-at-pupman-dot-com
Subject: Re: TC Electrostatics (fwd)
From: lod-at-pacbell-dot-net
Date: Mon, 06 Jan 1997 20:43:02 -0800
Subscriber: lod-at-pacbell-dot-net Mon Jan 6 22:34:56 1997
Bert Hickman wrote:

> Greg,
> 
> Thanks! I'll assume good pulse-rated caps and good, high-Q, construction
> techniques are a given. After looking at Robert Stephen's video, and
> reviewing the data from Chuck Curren on the Cox'es coil, I'm beginning
> to think that rotary quenching performance may not be nearly as critical
> as I once thought. Bang size and rep rate have got to be key parameters.
> In the final analysis, brute force power can overcome _lots_ of other
> system inefficiencies! :^) 
> Another big factor would have to be sizing the ROC of the top terminal
> and E-field control so that it does not break out prematurely, and that
> streamers don't preferentially strike downward to the primary. 

I've always wondered about this:  doesn't the presence of a streamer on
the top electrode completely compromise the break-out voltage by acting
as a wire, or a pointy conductive stick?  After all, doesn't the next
output pulse usually build upon the end of an existing streamer?

> Certainly
> the length of the secondary is also a significant factor - it must be
> long enough to provide adequate physical seperation between the toroid
> and the primary as well as to itself on a 2-coil system. Larger
> diameter, squatter coils might otherwise be better performers with their
> higher L versus C ratio. 

What do you see as the optimum value for Zo (Zo = sqrt[L/C])?  I used to 
think that something around 20,000 ohms was optimum, but now I'm starting 
to think that values closer to 35,000 ohms might be better.

> Electromagnetic coupling between
> primary:secondary should be as tight as insulation will withstand - and
> probably close to a "magic" value to reduce energy-stranding in the
> primary circuit. I'd really like to see if 0.28 could be achieved on a
> 2-coil system! A low-impedance path between the coil base and the other
> "plate" of the secondary's capacitance is a significant factor, more-so
> with lower Zo coils.
> Coil Zo itself is a poser! Obviously using too fine a wire gauge can
> hurt performance, but a lot has to do with whether its direct driven
> (no-one will dispute RH's results using a 30 Gauge resonator!), and the
> degree to which the coil is behaving as a distributed transmission line
> or a lumped LC.  Results on your big coil, and Cox's Milwaukee Museum
> coil seem to indicate that heavy topload C is not an automatic
> prerequisite for great performance!! BTW, do you have any conclusions
> from the Zo/coil performance information you were gathering last year?
> 
> Still lots of mysteries in coiling, Greg!
> 
> Safe coiling to you!
> 
> -- Bert --