Re: Redesigning/tuning a coil

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

Original poster: "June Heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

John: Your statements are correct , but lets discus the practical. I use
solenoid, cone and flat primaries. The flat coil has the least problems ,
The free standing solenoid coil has the most problems  with arc over over
coupling etc. The cone coil gives the best and requires more mechanical
thought and work. In all it is a choice you make. The flat coil is easy and
fast to make and requires the most copper tubing to make.( 100 ft coil) A
solenoid wound on a PVC pipe coil form is less problems than a free standing
coil but it requires more work.
  Robert   H
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, April 20, 2004 7:45 AM
Subject: Re: Redesigning/tuning a coil


 > Original poster: "john cooper" <tesla-at-tesla-coil-dot-com>
 >
 > Maybe I've a poor understanding of this but I've been laboring under the
 > impression that the sloped primary allows for a stronger coupling of the
 > prim to sec as it reduces the distance from those outside turns to the
 > sec.  It seems to me that the sloped prim may also 'shape the field'
 > somewhat or better direct it towards the sec.  My memory tells me that the
 > electric field diminishes as an inverse square function with respect to
 > distance, and that mag fields fall at an inverse cubed or 4th?  If a
 > tighter coupling than a flat prim would provide is not beneficial to a
 > particular coil then I can see that it wouldn't be of much use.  Have I
got
 > this all wrong, partly wrong?  I think I probably need to spend some
 > quality time with 'Electromagnetic Waves and Radiating Systems' by Edward
 > C. Jordan/Keith G. Balman to brush up on the basics.  Hmmmmm.
 >
 >
 > ---------- Original Message ----------------------------------
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date:  Mon, 19 Apr 2004 21:31:13 -0600
 >
 >  >Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
 >  >
 >  >Tesla list wrote:
 >  > >
 >  > > Original poster: "john cooper" <tesla-at-tesla-coil-dot-com>
 >  > >
 >  > > Regarding the primary angle:  I ran through that experiment on my
largest
 >  > > coil a few years ago and 18 degrees of slope was the maximum
allowable
 >  > > primary slope on that coil.  Primary is about 19 turns of 1/4" cu and
I
 >  > > believe it was tapped at 17 turns.  1 degree over that 18 and the
primary
 >  > > field wouldn't cover the top of the secondary and, believe me, you
could
 >  > > tell where it was hitting the secondary, an inch or two below the top
 >  > > turn.
 >  >
 >  >(?!) This magnetic field is working in a quite unusual way. The
 >  >exact distribution of the magnetic field along the secondary coil
 >  >doesn't have any particular importance. What matters is
 >  >the coupling between the coils. Excessive inclination can
 >  >result in excessive proximity between the coils, and problems with
 >  >the electric field along the secondary coil, causing "racing sparks"
 >  >along the secondary coil and primary-secondary sparks. Nothing related
 >  >directly with the magnetic field.
 >  >
 >  >I don't see any reason for the use of inclinated primary coils. A
 >  >flat coil generates adequate coupling and is easier to build.
 >  >
 >  >Antonio Carlos M. de Queiroz
 >  >
 >
 >
 >
 >
 >
 >