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Re: [TCML] primary tubing
Thanks, Gary, for your input. As is often (usually) the case with most
situations presented on the list, there is usually more than one way to
accomplish something. I suppose the proof, as they say, is in the pudding.
In this case, I think "pudding" :) the aluminum primary to use on an
existing coil with known results will prove it out, one way or another. If I
understand correctly, I should use a diameter larger than the 1/4" copper
I'm currently using. We shall see,
Ps. What would your other reasons for not using aluminum be, if not the
I have refuted this oft-repeated but mistaken belief of yours that aluminum
exhibits some frequency-dependant resistance, several times in the past and
I will continue to do so. It does not, to any significant degree. I have
made frequency-sweep measurements of the AC resistance for many different
conductor geometries, including Al vs. Cu. Of course the aluminum has a
higher resistance than copper, but this is due to the intrinsic resistively
difference between them and is NOT frequency dependant for the frequencies
that we are interested in. If the aluminum conductor diameter is scaled up
to compensate for the higher resistively, it's a wash.
There are many good reasons to choose copper conductors over aluminum and I
wouldn't use anything but copper myself, but frequency-dependant resistance
is not one of them. Please either supply quantitative evidence of your
claim, or stop propagating this myth.
To Neal's question - Primary resistance is a very bad thing for Tesla coils.
Every (reasonable) effort should be made to minimize tank circuit
resistance, if you're going for maximum performance (and not everyone is).
Regards, Gary Lau
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
Behalf Of DC Cox
Sent: Friday, November 06, 2009 5:54 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] primary tubing
At RF frequencies aluminum is a poor conductor as compared to copper. Use
copper for HF applications. Alum will limit your peak RF current,
you don't want to do. Peak RF current determines peak magnetic field
of course links all your power into the sec inductor.
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