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Re: Low Voltage Primary



Hi Terry, all,


> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
> 
> Hi Max,
> 
> 	If I left the cores in, it would be "just another transformer" where the
> step up is controlled by the ratio of the windings.  However, with the
> cores removed, I can reach much higher voltages through the resonant rise
> effects of a Tesla coil where the step up is controlled by SQRT(Ls/Lp) (a
> much higher value).  With the cores still in, a GM coil will only get 3 to
> 4 inch sparks if it is really driven hard.  But running them as Tesla coils
> without the cores, allows 13.25 inch arcs which is 4 times longer.  Also,
> at very high voltages (~200kV) the steel cores will saturate and eat up the
> energy.  The neat thing is that the vacuum impregnated epoxy cores are
> designed for extreme environments which allows them to withstand these
> tremendous voltages (for a while at least).

I'd like to inject a couple of comments if I may. Last year  (or was it 
earlier this year?),  I went through and exercise to see whether one 
could actually do better than Ns/Np in a TC circuit. What I found 
was that one could - IFF the secondary had the form factor of a 
typical primary and vice versa. Remember that  SQRT(Ls/Lp) boils 
down to Ns/Np (try it using Wheeler's formula and if that doesn't 
convince you, have a go from Medhurst's point of view as well. Of 
course a physically short secondary isn't much use in any kind of 
steup transformer.  That post should be in the list archives.

?
Malcolm
<snip>