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Re: Primaries
Tesla List wrote:
>
> >From MALCOLM-at-directorate.wnp.ac.nzTue Sep 24 22:21:30 1996
> Date: Tue, 24 Sep 1996 17:39:14 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Primaries
>
> Thanks for the input Bert.
>
> > Good luck on the new coil! A 45 pF topload on top of a 16" diameter coil
> > should make for a pretty good sized coil for a 2.3 kW system! Re: gap
> > losses - it seems like nature and physics has conspired to limit primary
> > Q. The negative resistance characteristic of the gap arc is a fortunate
> > phenomenon(!) - think of the losses if it had a positive characteristic!
> > Unfortunately, it seems that whatever current primary current levels we
> > run, the arc compensates (and limits us) to a primary Q of 10-12.
> >
> > One way to improve the system efficiency would be to maximize the
> > coupling coefficient so that more energy transfers to the secondary
> > quicker, reduccing the duration of the gap losses. If we can succeed in
> > quenching the gap immediately after the first energy transfer, we've
> > should maximize power transfer. With a 2-coil system, this is probably
> > "practically" max'ed at k=0.22. If you're able to hit higher "magic" k's
> > without breaking down the secondary or flashing to the primary, AND if
> > you can quench the gap, you should be able to break 2-coil records.
> > Otherwise it looks like a maggie is the only way.
>
> It might very well come to that for record setting. You're absolutely
> right IMO about the slightly more desirable characteristic of the
> gap too. But I would like to get to 8 feet if I can with a 2-coil
> config. If not.... BTW, I am planning on using 10J bang size with a
> rep rate around 200+ BPS.
>
> > Good Luck!!
>
> Thank you,
> Malcolm
Malcolm,
I haven't tried pushing the coupling coefficient on my 2-coil system
beyond 0.21. However, the Behr Build50 seems to dramatically reduce
corona and has eliminated any inter-turn flashovers - there's absolutely
no sign of any pre-breaksown phenomena in a dark room running flat-out.
You may want to try using an epoxy under/overcoat perhaps with
supplementary LDPE sheeting between the primary and secondary to see if
you can push k to 0.28. If it works you'll definately have a winner! If
not, you can always back it down to and still be in the game.
-- Bert --