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"The Mighty Corona Cone"
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From: D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Wednesday, February 11, 1998 11:55 AM
To: Tesla List
Subject: Re: "The Mighty Corona Cone"
to: Steve
Two inches is too far away from the top of the sec. coil in a high perf.
unit. We set ours at 3/4 inch max on most all of our oscillators. At 1/2
to 3/4 inch your "corona cone" should disappear.
DR.RESONANCE-at-next-wave-dot-net
> From: SBJohnston-at-aol-dot-com [SMTP:SBJohnston-at-aol-dot-com]
> Sent: Tuesday, February 10, 1998 3:41 PM
> To: tesla-at-pupman-dot-com
> Subject: "The Mighty Corona Cone"
>
>
> Hi list:
>
> I added a 17" dia toroid made of 4" aluminum duct to the top of my 16"
dia
> 48" long secondary, yet the top few turns are still streaming with
corona.
> In fact, the effect may be stronger with the toroid than without. It is
a
> solid, sharply-defined, glowing vertical cone streaming up and away from
the
> coil and topload.
>
> Using my URM-25 signal generator with Hi-Z output and built-in VTVM
indicator
> (perfect for this job!) I measured the secondary's resonant freq as134
kHz
> bare and 119 kHz with the top loading. My 11-turn primary is resonant
at
> about 116 kHz with my 0.018-0.020 uF tank cap, so it should be tuned OK.
I
> distrust the primary measurement to some degree, as I would expect the
> resonance of the secondary to affect the primary .
>
> Breakout was suppressed with the toroid in place until I used an inch of
wire
> to encourage the discharge out the side. The strikes and streamers from
the
> toroid were only slightly stronger than with just the top insulator bolt
or a
> vertical wire as top terminal.
>
> As I increase the input voltage, the corona from the top few turns of the
> secondary increase proportionally more than the streamer and strike
length
> from the top terminal. Before I redesign the exciter for increased
output,
> it looks like I need to supress this wasteful discharge from the top
turns of
> the coil.
>
> Initially, I mounted the toroid directly on the top of the six inch
ceramic
> insulator. This placed the bottom of the toroid within a few inches of
the
> top of the coil. I raised it up at least 8 inches higher on a feed-thru
> insulator stud - no difference, I was still running "The Mighty Corona
Cone".
>
>
> Short of submerging the entire coil in mineral oil, any suggestions?
>
> Steve Johnston
>
> sbjohnston-at-aol-dot-com
>
>