Re: stepped leaders
>From jim.fosse-at-bdt-dot-comFri Aug 23 22:40:59 1996
>Date: Fri, 23 Aug 1996 17:18:06 GMT
>From: Jim Fosse <jim.fosse-at-bdt-dot-com>
>Subject: Re: stepped leaders
>>From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
>>Subject: Re: stepped leaders
>>You then conclude: "The multiple beat envelope one gets shows that
>>the system is vastly overcoupled before spark production." Yes I
>>agree with you, this seems intuitively correct.
>>DING, light going on! This is the scientific explanation why on a sizeable
>>system, when big power is going in, and no streamers are yet coming out, the
>>rotary break is beating itself up! (with greatly increased light
>>output). I used to give this the casual explanation that the input energy was
>>merely 'piling up' at the break contacts, but you've just cleared it up for me!
>Could I interject a thought on this condition? Under this condition,
>the TC secondary IS acting like an unterminated transmission line with
>the attendant high SWR that this condition implies. (Standing Wave
>Ratio can be thought of as the ratio of forward power to reflected
>power) With no load at the end of the transmission line (no sparks at
>the discharge terminal) and all the power sent down to the far end of
>the secondary is reflected back to the near, driven, end.
>This reflected power is transformed by the transformer action of the
>TC secondary to TC primary coupling and is dissipated in whatever
>lossy components are in the primary circuit. Given most construction
>methods used by the coilers on this list, the primary is of low R, the
>cap is of low D, that leaves the spark gap as the losseist component.
>It starts dissipating the power of the system.
Your description as given here is exactly what I thought before
Malcolm displayed his clever insight into the changing K factor. I
think you are absolutely correct, and I think Malcolm is as well. You both
pass go and collect $200, (One of you guys want to loan me some
>One of my unanswered questions: is the output voltage of the TC
>secondary: a) strictly the input voltage multiplied by the turns
>ration of the secondary to primary? b)input voltage multiplied by the
>turns ratio multiplied further by the 1/4 wave transmission line
>properties of the secondary? or c)some combination? I am waiting to
>measure this until I can build some type of metering scheme; field
>mill or HV resistive divider.
>If the answer is b or c, then the voltage across the spark gap is much
>greater under no load conditions than under a loaded condition because
>the reflected wave is of greater voltage that the simple turns ratio
>would provide and is transformed backwards only by the simple
>transformer action of the secondary:primary.
>Any thoughts on the transmission line voltage multiplication effect?
Action a. applies only when the coupling between primary and
secondary is tight. The turns ratio rule will apply. I have
measured this with high predictability and accuracy with tightly
coupled vacuum tube powered CW coils. In a classical 2 coil design, resonant
rise through standing waves predominates when K is made low. As I
understand it the lower you can get K the higher the SWR ratio
becomes. Provided that ohmic leakage losses, corona losses and radiative losses
can be controlled, this equates to higher developed output voltages. The
reason a magnifier works so well is it is the extreme case of
reducing K to zero! The final resonator can swing unimpeded without
any magnetic coupled loading to its driver coil.
It would be interesting to measure the spark gap voltage under
conditions of power in, no streamers out. I think you are correct in
postulating that the gap voltage will increase by virtue of greater
reflected energy back into the primary coil through mutual coupling
to the swinging but unloaded secondary.
Very interesting train of thought!