RE: Math help...

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi John,

On 12 Jul 01, at 17:50, Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-worldnet.att-dot-net>
> 
> 
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, July 11, 2001 10:14 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Math help...
> 
> 
> Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
> 
> Tesla list wrote:
> >
> > Original poster: "Bert Hickman" <bert.hickman-at-aquila-dot-net>
> 
> > The measurement was done by:
> > 1. Using a "magic" value for coupling (so that both the voltage and
> current
> > simultaneously hit zero upon completion of an energy transfer
> > 2. Preventing breakout from the toroid even at peak secondary voltage
> > 3. Permitting the peak secondary energy to transfer back into the primary
> > circuit (easy, since it's virtually impossible to quench the gap under
> > these conditions)
> > 4. We then measure the primary capacitor voltage once the secondary's
> > energy has completely transferred back into the primary capacitor.
> 
> This is an excellent method. If you see a linear decay from beat to
> beat, the energy transferred to the secondary would be the average
> between the energies measured at the primary. If the decay is
> exponential,
> use a geometrical average.
> You can even find an "effective primary resistance" that accounts for
> all the losses, and an "effective Q" for the circuit (although there
> are actually two resistances and two Qs).
> 
> Antonio Carlos M. de Queiroz
> 
> ---------------------------
> 
> Antonio -
> 
> In the losses you mention above what are the magnetic circuit flux losses in
> the transfer of energy between the pri and sec coils? How do you calculate
> these flux losses?
> 
> With the "effective primary resistance" what part does the magnetic flux
> losses play?
> 
> John Couture

All losses in effecting an energy transfer are reflected in the Q's 
of the circuits involved. Trying to separate the loss components from 
each other would be difficult (save that one can quantify the 
proportion of the losses occur in each circuit). One can broadly say 
that losses in the secondary circuit are shared between radiation, 
resistive in the secondary windings, the ground path and hysteresis 
losses in the dielectrics, and those in the primary are attributable 
to dielectric losses in the capacitor/s, the winding itself and the 
gap plus a bit of coupling into other lossy elements (e.g. direct 
coupling to a high resistance in the ground below the coil).
     One could point to those sources and minimize each, e.g.
Primary - raising the primary higher reduces coupling into the ground
        - reducing the primary currents reduces the gap loss and the 
          winding loss
Secondary - increasing spacing between the secondary and other 
            objects reduces losses due to coupling into other 
            parasitic circuits nearby
          - improving ground conductivity and shortening the ground
            strap decreases losses in the ground path
          - using a lower loss material for the coilform reduces
            dielectric losses
and so on.

     Measuring the improvement by changing these parameters one a t 
time could give a useful indication of the proportion of the total 
losses each was contributing to.

Regards,
malcolm