Re: Redesigning/tuning a coil

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

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