Re: Electrical Properties of Aluminum and Network Analzyer was : RE: Brass

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

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>


Terry,

That test is severely flawed:
First, we already know that for the same cross-sectional area, aluminum has
a higher resisitivity per unit length than copper.  No need to use
a network analyzer for this.
Secondly, a network analyzer is not going to tell you squat about how an
oxidized coil performs under high rf current conditions like those occurring
in a
tesla coil.  You really need to make the measurements somehow at the rated
power levels you are going to operate at for the data to be meaningful.

The Captain



 > We have RF effects forcing the current to the outside and resistive
effects
 > forcing current in....  Exactly where the current goes and what the loss
 > is, is an interesting problem I am sure ;-))  In a few days I am getting
 > some high power RF coils that are aluminum heavy plated with silver.  They
 > work well since the currents travel in the thin silver layer.  What will
be
 > fun to see is what happens if the plating gets a crack.  We "think" it
will
 > incinerate.  But have to see for sure.  Stay tuned...
 >
 > I or Gary Lau may be able to get two coils that are exactly the same
 > dimension but one is copper and the other aluminum and test the resistance
 > on a fancy HP machine.  Soaking or boiling the aluminum one in salt water
 > will certainly oxidize it well.  I'll ask the guys that know how to run
the
 > HP network analyzer beast to see if that is "easy" to do.
 >
 > Cheers,
 >
 >          Terry
 >
 >
 >
 >
 >