Re: just a thought

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

Original poster: DRIEBEN-at-midsouth.rr-dot-com 

Hi Malcolm,

My  first two or three coils had helical primaries and they also
worked good. They were, as you say, over twice the diameter of
the secondary and were actually mounted so that the loest turn
was actually ABOVE the horizontal plane of the bottom turn of
the secondary by a couple of inches. They did perform well and
did give good coupling but I did have to be careful about their
vertical placement as raising the primary just a fraction of
an inch could cause the coil to go from running smoothly to
the secondary being covered with racing sparks. Optimal coupling
seemed pretty critical.

David Rieben

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
Date: Saturday, May 8, 2004 11:53 am
Subject: Re: just a thought

 > Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
 >
 > On 7 May 2004, at 8:17, Tesla list wrote:
 >
 > > Original poster: Jimbo07031982-at-aol-dot-com
 > >
 > > Has anyone ever attempted to use 2 primary coil's mounting the
 > first > one the usual way slanting up and the 2nd on top of it
 > slanting > downwards the only real problem I see with this idea is
 > the tuning for
 > > it would take for ever. Just a thought.
 >
 > I can't see any advantage and one of the obvious disadvantages would
 > be to reduce pri-sec clearances. A helical primary would be a much
 > better option. BTW, while I know they're not the flavour of the year,
 > they do work well and score better inductance of the money spent on
 > copper. The best coils I ever built all had helical primaries. It is
 > important to make the diameter at least 2x that of the secondary and
 > perhaps larger while getting the turn-turn spacing as small as
 > possible.
 >
 > Malcolm
 >
 >
 >