[TCML] Secondary coil strikes

[Kurt Schraner]

Carl, I was in belief of the same you're talking in 1999, and installed such 
copper corona turns (not rings!) on my 8" Twin sec's, in order to avoid 
corona at the top of the secondary, somehow following Bill Wysock. However 
with unsuccessful result. For construction see:

http://home.datacomm.ch/k.schraner/tc8inch.htm
http://home.datacomm.ch/k.schraner/corona_wdg.jpg

OK, one may see, the gap to be too wide, and having
no real radius at the edges; a beginner's mistake, perhaps.

At the edges of the ring-gap I was getting breakout of "streamers" to the 
air, not so welcome :-( I closed the corona turn to a ring, and had no more 
problem, neither with corona nor breakout, and most important: no 
diminishment in performance. To me is clear: You are right in principle. But 
having a shorted ring at the top (where currents are quite small), and on 
the low end of the sec., where the primary is close (with huge currents), 
are different worlds. Have not seen later, any toroid, able to suppress 
corona at the top of the sec, and diminishing performance. I don't care 
since about "shorted turns" at the top since, if they are a little up from 
the sec-top turn (say 0.5-1" or so).

Just my 2 cents.

Kurt

-----Ursprüngliche Nachricht----- 
From: Carl Noggle
Sent: Monday, May 14, 2012 4:59 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Secondary coil strikes

You shouldn't lower your toroid, because if it is less than about half
of the winding diameter away from the coil top, it will act as a shorted
turn and reduce your performance.  You can make a turn around the top of
the coil with 1/2 inch copper tubing right next to the wire, but leave a
break of 1/8 inch or so to avoid the shorted turn.  Connect this tubing
to the top of the secondary.  Hopefully this will stop arcing from the
top turns.

Good luck---

Carl