RE: [TCML] Primary selfC

["Lau, Gary" <Gary.Lau@xxxxxx>]

I would agree that a spiral ribbon is not the best choice for a high-Q primary.  When I made AC resistance measurements on several different primary conductors, all of the same inductance, a 1" x .03" copper ribbon showed a slightly higher AC resistance than a coil of 1/4" Cu tubing, over all frequencies of interest, despite having less than half of the tubing's DC resistance.  I attributed this to eddy currents; not sure how this differs from proximity losses.

http://www.laushaus.com/tesla/primary_resistance.htm

Regards, Gary Lau


> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Paul Nicholson
> Sent: Saturday, July 26, 2008 5:26 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Primary selfC
>
> This compact ribbon primary is proving to be interesting. The
> high turn-to-turn capacitance is turning out to have a
> non-negligible contribution to the internal capacitance of
> the coil, which as a result, affects the coil's effective
> inductance and will lower the resonant frequency.  By how much?
> I hope to be able to estimate this, or at least point the way.
>
> I'm brewing up a more thorough reply which goes into the matter
> in some detail.  I'd like a few more days to work on it so that
> I can try to adapt some of the tssp software to this type of
> coil - not something we've looked at before.
>
> Meanwhile, have the proximity losses of this design been
> considered?  If high Q is a design priority, would a helical
> ribbon rather than a spiral ribbon not be a better proposition?
> --
> Paul Nicholson
> --
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