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"The Mighty Corona Cone"


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From:  FutureT-at-aol-dot-com [SMTP:FutureT-at-aol-dot-com]
Sent:  Wednesday, February 11, 1998 11:59 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: "The Mighty Corona Cone"

In a message dated 98-02-11 04:58:38 EST, you write:

<< snip>
> 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
  >>

Steve,

I recommend the installation of a mighty toroid, if you have the power 
available to drive it.  On a sixteen inch dia. coil, I would think you 
would want to have at least a 36" dia. toroid, or larger.  A larger
toroid will definitely suppress the corona, and also give a much 
more powerful spark output, but you need sufficient power input
for the large toroid.  For instance with the 36" dia toroid, you may
need 3kW or more.  Generally, it's good to have plenty of toroidal
overhang over the secondary.  Generally, you want to see a spark
that is at least twice as long as the toroid is wide.  For instance,
my 20" toroid TC gives a 42" spark, and my 26" dia toroid TC gives
65" sparks, but you need enough power input.  You can of course
obtain sparks 3 or 4 times the toroid dia, but this takes even more
power input.

But aside from the above, did you retune outward when you
added the 17" dia toroid?  If the tuning was left the same as 
without the toroid, this can cause breakout from the top turns. 

Also, if the coil is underpowered, the lack of power may be 
contributing to the corona problem by hindering the spark 
break-out from the toroid.  I seem to remember in a previous
posting that you said the coil was underpowered, and this may
be a large part of the problem.

In any case, it's definitely a solveable problem.

John Freau