Re: [Bulk] Re: [TCML] Secondary coil strikes

["drieben" <drieben@xxxxxxx>]

Hi Kurt,

You bring out a really good point here. I mean
let's face it, the toroid topload itself would actually
be a "shorted turn", wouldn't it? Yet you don't hear
of anyone decrying the use of a topload for a coil
because of the "shorted turn", do you? And, as you
have pointed out, the gap edges of your ring only
instigated breakout where you DON'T want it! Now
as for a strike ring around the outer perimeter of the
primary coil, then you bet, you do NOT want a con-
tinuous "ring" as it will indeed noticably rob from the
power and performance of the output streamers (been
there, done that).  Just like you stated, the induced
currents at or near the same plane as the primary coil
are indeed huge and a shorted turn here is a problem.
OTOH, induced currents are quite small an inconse-
quential in the vicinity of the topmost winding of the
secondary and therefore, the "shorted turn" really
isn't an issue here.

David Rieben




----- Original Message ----- 
From: "Kurt Schraner" <k.schraner@xxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Tuesday, May 15, 2012 8:01 AM
Subject: [Bulk] Re: [TCML] Secondary coil strikes


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

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