Re: K Factor & Mutual Inductance

            Re: K Factor & Mutual Inductance
            Mon, 07 Apr 1997 06:49:31 -0700
            Bert Hickman <bert.hickman-at-aquila-dot-com>
            Stoneridge Engineering
            Tesla List <tesla-at-pupman-dot-com>

Dr. Resonance:

I agree with your assessment that coupling coefficient should be
independent of power level. Coupling coefficient defines the portion of
magnetic flux that is shared between the primary and secondary, and is a
function only of relative geometry and spacing between the two for air
cored coils. Although optimal primary running frequency seems to lower a
little bit under high power operation, this is not attributeable to any
changes in the coupling coefficient, but more likely in effective
secondary:toroid loading capacitance after the region around the top
becomes heavily ionized. Also, estimating optimal quench-time as a
function of fr and k requires adjustment - but this is a function of gap
energy losses and k.

-- Bert H --

Tesla List wrote:
> Subject:
>         Re: K Factor & Mutual Inductance
>   Date:
>         Mon, 7 Apr 1997 04:57:32 -0700
>   From:
>         "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
>     To:
>         "Tesla List" <tesla-at-poodle.pupman-dot-com>
> To: John Couture
> Hi John:
> We normally think of coeff. coupling being independent of system power,
> ie,
> if you ignore the effects of additional electric field capacitance above
> the sec. coil (usually on 5% or less anyway) then the coeff. coupling
> measurements should be the same with a sig. generator and scope vs. a
> powered up system.  Does your equations somehow tie "power" into the
> coeff.
> coupling equation??
> I know the relationship between mutual inductance, coeff. coupling, and
> Q,
> but was wondering how power fits into the system with regard to
> calculations?  Any comments greatly appreciated in this area.
> We normally tune up systems using a sig. generator (vacuum tube type for
> higher output) and scope, and then make an adjustment for actually power
> up
> operation.  There seems to be a direct linear relationship between these
> two primary tap positions.  A small extrapolation is usually necessary
> for
> high power systems operating over 5 KVA.
> We plan to do some more direct research in this area this summer and try
> to
> develop an exact difference so as to develop a simple equation or simple
> ratio/proportion which can be applied to most coil systems.  Richard's
> systems with high coeff. coupling might respond differently.
> Any comments -- John or Rich H., et al   -- on your thoughts and
> observations.
> DR.RESONANCE-at-next-wave-dot-net