Re: 15" coil project

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

Original poster: "G by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bog-at-cinci.rr-dot-com>

What a great idea Malcolm! I'd be glad to beta test your new design program! :P
Gregory

>
>Unfortunately, it is difficult to separate the wheat from the chaff
>so easily. Your conclusion takes only a couple of factors into
>account. One not mentioned is the winding length, something to which
>I would attach the utmost importance. My question is: was the voltage
>handling capability of your two coils the same? (Bet = no).
>
>     On the question of wiresize and efficiency, a bunch of
>measurements I did on a range of coils showed clearly that there is
>an optimum sized topload for a given secondary and that if you start
>with a wiresize that is too small, adding topload to the bare coil
>will cause its Q to start diving. A more useful coil will have a
>sufficiently large wiresize that causes its Q to go UP as topload is
>added (until some point where it starts to go back down again as the
>L/C ratio is dropping). An ideal coil will have a topload sized for a
>peak in Q with the coil, a radius of curvature that puts it right on
>the edge of breakout for the voltage being developed, a sufficient
>height for the voltage being developed (to prevent flashovers), and a
>primary surge impedance in the 50 - 100 Ohm range with sufficiently
>large conductors in all primary components.
>
>Regards,
>Malcolm