Re: Ratio of primary outer dia.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Esondrmn-at-aol-dot-com 

In a message dated 12/7/03 3:46:24 PM Pacific Standard Time, 
tesla-at-pupman-dot-com writes:


>Hello,
>
>Does someone have a rule of thumb for determining  primary outer diameter
>based on secondary diameter and height?
>I did an archives search, but came up with nothing definitive.  I am sure
>that there is a ratio for optimum performance.  Also, if John Couture is
>reading this, are you planning on publishing an updated version of your
>construction guide?  Mine is from the early 90's, and I was curious if you
>are planning to integrate some of the last decade's developments into a new
>book.  I certainly hope so.
>
>Thanks,
>John Richardson


John,

On my coils, which use flat primaries, the outer diameter of the primary 
just ends beigh what it is by default.  Depending on the secondary size and 
input power, I decide what I want for the I.D. of the primary, tubing size 
and spacing.  I always wind the primary for 12 to 14 turns.  I prefer to 
run my coils with at least 10 turns used on the primary to keep the surge 
impedence lower to make it easier on the caps.  The primary on my 6" coil 
is about 26" in diameter with about 2.5" inside clearance.  My 3" coil 
primary is about 16" with about 1.5" inside clearance.

Ed Sonderman