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RE: [] conical secondary (fwd)



---------- Forwarded message ----------
Date: Sat, 16 Jun 2007 11:47:04 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: [] conical secondary (fwd)

Sorry, but I've yet to see evidence of any functional advantage to using
conical (or pancake) secondary coils vs. cylindrical ones.  

That Tesla used conical coils doesn't make it best.  He used cotton
covered wire, beeswax, and salt water caps, but I wouldn't count these
as best practices.  

Yes the coupling will be higher if the secondary base is wider, but one
simply has to move the primary closer to achieve whatever coupling is
desired.

Why would corona losses be reduced with a conical secondary?  With a
toroid atop a cylindrical secondary, I see no corona.

Claims that conical (or pancake) secondaries are more efficient appear
to be lacking evidence.  Jeff Behary's site (correct URL is
www.electrotherapymuseum.com) is richly decorated with photos of
non-cylindrical secondary coils, but there are precious few words
describing the rest of the coil components by which to judge just how
efficient the coil might actually be, and nothing actually making a fair
comparison.  Making a coil simply produce photogenic sparks does not
demonstrate superior efficiency.

Regards, Gary Lau
MA, USA




> Date: Fri, 15 Jun 2007 19:25:06 -0700
> From: wysock@xxxxxxx
> To: Tesla list <tesla@xxxxxxxxxx>
> Cc: William.C.Wysock@xxxxxxxx
> Subject: Re: [] conical secondary (fwd)
> 
> Hello Finn and all.
> 
> It has been quite a while since I've written to the List.  This
business about conical
> secondary coils has caused me to now reply.  Finn, you are right.
winding a conical
> secondary coil (regardless of size) from the small diameter end to the
large end
> is the only way to go.  There are techniques that one can use to
support the first
> 10 or so windings to be held in place as you continue to wind.
> 
> Why use a conical coil form?  It has nothing to do with "old classic
designs".
> Rather, it has to do with placing the greatest amount of the secondary
coil
> inductance in closer proxcimity to the primary coil.  Think about it.
There is
> another advantage to a conical secondary coil design.  That is,
reduced
> corona leakage stress at the top of the coil due to its shape (not
withstanding
> whatever "top load" electrode geometry you chose to use).
> 
> Proof of how successful this secondary coil design can be?  Just look
at the
> Griffith Observatory coil on my web site at: http://www.ttr.com.  Also
please
> see the two one-to-one copies I've made of this coil: GPO-1 and GPO-2.
> There is also a (mini) version of GPO-2 that is linked to my web site.
> All these coils are up and running in a public venue setting.
> 
> It interesting to note, that Tesla himself, in his first (medium size)
resonator coil
> at his 5th Ave. laboratory before it burned down, ( see the image of
this coil
> in the Beograd book "Tribute to Tesla"), and also his first secondary
coil design
> at Colorado Springs (in the book Colorado Springs Notes), were also
conical
> secondary coils.
> 
> When it comes to design details of "what is the most efficient form of
r.f.
> resonator coil system"?  It goes like this:
> 
> Least efficient (but most practical design to build): cylindrical
secondary.
> More efficient (but difficult to wind): conical secondary.
> Most efficient (but the hardest to build): pancake secondary and
primary.
> 
> My friend and colleague Jeff Behary, has been making many new
breakthroughs
> in this last area of investigation.  Please see his web site at:
> http://www.turnofthecenturyelectrotheripymusuem.com.
> 
> Best regards,
> Bill Wysock.