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Re: helix vs. flat-spiral primary
HI Dan,
Guess who's interested (surprise surprise):
> Original Poster: "Dan Kline" <ntesla-at-ntesla.csd.sc.edu>
>
> Hi all,
>
> I'm wondering a little about how magnetic field shaping of the primary
> might affect the coil system...
>
> (excerpts from other emails):
>
> "A flat spiral, (it seems), might affect a smaller
> region of the secondary, but with a much denser field. A sharp pulse to a
> few secondary turns, rather than a "thin" wipe to a lot of turns, like a
> helix might do. Things might be more efficient that way."
I don't think the shape of the primary has anything whatsoever to do
with the waveshape feeding the secondary. The thing is oscillating at
Fr whatever shape it is.
> "I'm thinking of it sorta like this: If I have a drum, and I hit it with a
> drumstick, I get a sharp "rat-tat" sound. If I hit it with one of those
> leather chinese-gong hammers, I'll get a softer, more "mushed" sound. The
> enery transfered would be the same, but I'd get different outputs of sound.
> I was thinking that the narrower field of flat spiral primary would be like
> the drumstick, and the helix would be like the soft mallet. Or it might not
> matter at all. I just got this idea from trying to visualize the magnetic
> fields of the different-shaped primaries."
>
> Comments anyone?
That bit of speculation has merit IMHO. Think of the "steel ruler in
the vice" analogy and how it feels when you waggle it with your
fingers at different heights. (BTW - the "currents" are in phase in
that model everyone!). Undoubtably the flat spiral will couple most
strongly to a smaller portion of the winding than a helix would. I
wonder if a performance comparison should be done for both types
running the same k and starting at, say, the bottom turn. There might
be subtle variations in the way the secondary behaves that
instruments could detect.
Regards,
Malcolm