RE: Coil Design

        RE: Coil Design
        Mon, 14 Apr 1997 04:58:56 +0000
        "John H. Couture" <couturejh-at-worldnet.att-dot-net>
        Tesla List <tesla-at-pupman-dot-com>

At 10:01 PM 4/13/97 +0000, you wrote:
>            RE: Coil Design
>       Date: 
>            Mon, 14 Apr 1997 08:20:37 +1200
>       From: 
>            "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
>            Wellington Polytechnic, NZ
>         To: 
>            tesla-at-pupman-dot-com
>Hi Barry,
>>   From: 
>>         Benson_Barry%PAX5-at-mr.nawcad.navy.mil
>>     To: 
>>         tesla-at-pupman-dot-com
>> Hi Malcolm, All,
>> Interesting article.  I don't understand the sentence:
>> "This {mutual inductance} can be reduced or eliminated
>> by proper geometry where the loops overlap each other
>> such that the net mutual inductance is zero".
>A similar thing is done for induction-balance metal detectors. It 
>simply means the coils are positioned in such a way that coupling 
>between them is reduced to near zero (there's one for the critical 
>coupling enthusiasts :)  There was a short article in Electronics 
>Australia a year or two back which showed the method invented to 
>eliminate coupling between air-cored coils in early radio sets where 
>the coils were mounted in a line but at around 40 degrees or so lean 
>from vertical, all leaning in the same direction.
> ----------------------------------------------

  Malcolm, all -

 I haven't seen the article but have some questions. Are you saying that
mutual inductance can be "reduced or eliminated" for Tesla coils? What
be the advantage?

 It is obvious that it is a simple matter to reduce the mutual
inductance by
proper geometry as Benson stated. I once used this idea for a homemade
regenerative receiver. But I don't believe this is of much value for

 However, you said there were other design issues pertinent to Tesla
Can you elaborate for the benefit of the Tesla List?

 John Couture