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Re: Sphere/Toroid Comparison Chart

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

Hi Terry,

On 9 May 01, at 11:54, Tesla list wrote:

> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
> Hi Malcolm,
> I think the difference in the voltage profiles is more due to how the
> toroid messes with the fields around the top of the secondary instead
> of the shorted turn effect.  The top of secondaries seems to be very
> insensitive to the shorted turn top terminal.  If Paul is listening
> maybe he can explain more and what the effects of a split top terminal
> may be.
> Cheers,
>  Terry

I agree that appearances suggest that the short has little effect. 
That is what is so puzzling given the change in inductance. But how 
much of a change in inductance? 20%? I now remember applying the LC 
Analyser to measure this and the change in L was far far less than 
20%. I remember concluding at the time that it was because of poor 
coupling. In fact the change I measured amounted to 2% at most. So 
where did the 20% figure come from? I'm going to boldly swallow 
yesterday's comments about coupling and state that it disagrees with 
what I previously found. However, it should certainly be modelled at 
resonance. The thing I never did was to run a coil at power doing 
this to see if there was any major change in output, spark appearance 

 Greg Leyh also did the slit cut trick in his 40kW coil and noted the 
lack of change.