RE: Primary Winding (Strip vs Tube

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

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

While we are certainly talking about RF currents, I don't believe the
resistance of primary conductors really is affected by the frequency, at
least not for the frequencies that we are using.  In my experiments
measuring AC resistance of various primary conductors
(http://www.laushaus-dot-com/tesla/primary_resistance.htm), an aluminum
conductor behaved no differently than a copper conductor. AC resistance
was always in proportion to DC resistance.  A poor conductor is a poor
conductor, at DC and at TC frequencies.  There are many good reasons to
choose copper over aluminum conductors for a TC primary, but skin effect
is not one of them.

As far as a flawed statement, I assumed the discussion considered only
materials that common wires are made of, which would exclude carbon.  If
one needs to be told that dielectrics are a poor choice for wire
conductors, I don't think there's anything I could say that would help.

Gary Lau
MA, USA


Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>


I believe Gary was talking about RF currents --- like in a Tesla coil
primary circuit.

While aluminum and steel are acceptable at 60 Hz they are poor choices
for
HF RF currents.  The result is the peak current in the primary is
reduced
considerably.  Peak current (lots of it) is precisely what you want in a
TC
primary circuit, and you won't get this with steel or aluminum.  Stick
to
copper --- it's withstood the test of time by hundreds of TC
experimenters.

Dr. Resonance

  >
  >
  > I think your statement is a bit flawed...steel is by far not the
worst
  > conductor for a primary. Carbon would be much worse, then you have
any
form
  > of dielectric which is a far worse conductor than steel...
  >
  > ---Eric
  > ----- Original Message -----
  > From: "Tesla list" <tesla-at-pupman-dot-com>
  > To: <tesla-at-pupman-dot-com>
  > Sent: Tuesday, February 03, 2004 2:03 PM
  > Subject: RE: Primary Winding (Strip vs Tube
  >
  >
  >  > Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com>
  >  >
  >  > Steel of any sort is about the worst possible choice for a primary
  >  > conductor.  Yes, the rolls of steel shipping strap material look
tempting,
  >  > but the resistance of steel is very high.  Use only copper.  1/4"
copper
  >  > refrigeration tubing is common, inexpensive, easy to form, easy to
tap,
  >  > easy to solder, and performs very well - I recommend it.
  >  >
  >  > Gary Lau
  >  > MA, USA
  >  >
  >  >
  >  > Original poster: "Luke" <Bluu-at-cox-dot-net>
  >  >
  >  > I was toying with the idea of making my primary out of a strip of
  >  > metal.  Seems like it may be easier to construct a primary coil
from a
  > strip.
  >  >
  >  > Is spring steel ok for this or is copper the way to go?  Or are
there
any
  >  > other suggestions for material?
  >  >
  >  > The other question is how wide and thick is recommended?
  >  >
  >  > Luke Galyan
  >  > Bluu-at-cox-dot-net
  >  >
  >  >
  >  >
  >
  >
  >