Re: [] conical secondary (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 16 Jun 2007 14:49:49 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: [] conical secondary (fwd)

What Bill was identifying is that with a conical secondary, about 70% of 
the secondary inductance is in the lower wide section of the coil near 
induction field of the primary. The result for a flat primary and 
conical secondary is similar to the area of induction which a helical 
primary would put upon a helical secondary in close proximity, but 
without the overindulging coupling value. As a matter of fact, an 
inverse cone primary and conical secondary might be an interesting 
configuration regarding coupling capability.

I don't know that any of this makes for a more efficient coil. Here on 
the TCML, efficiency indicates a given spark length with the least 
amount of power (period). If the term "efficiency" is something other 
than that, it helps to be specific to it's use. There's not enough of us 
who have built conical secondary's to really make an opinion. Only those 
who have done both.

I think we all agree with Bill regarding contruction. Helical 
secondary's are definitely practical and likely why so many of us build 
to that geometry. Cone's are difficult to wind, and flat secondary's are 
a real pain in a$$. Winding it is easy, but building the supports for 
large flat coils is the difficult part.

Take care,
Bart

Tesla list wrote:

>---------- 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.
>>    
>>
>
>
>
>
>
>
>  
>