Re: Solid versus stranded Wire

To: tesla-at-pupman-dot-com
Subject: Re: Solid versus stranded Wire
From: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Thu, 18 May 2000 07:33:30 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Addressing a couple of points:

On 17 May 00, at 20:38, Tesla List wrote:

> Original Poster: "G. G. Ford" <swimp-at-home-dot-com> 
> 
> Tesla List wrote:
> 
> > Original Poster: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz>
> >
> > On 17 May 00, at 4:54, Tesla List wrote:
> >
> > > Original Poster: "G. G. Ford" <swimp-at-home-dot-com>
> > >
> > > About at TC Freqs, Solid better than Stranded wire...
> > >
> > > Is that because of the higher intrinsic inductance
> > > of smaller diameter wire, causing increased voltage
> > > drop?!
> >
> > No - inductance is lossless.
> 
> First of all, Inductance can RADIATE
>     and it can interact with ferromagnetic
>     materials to produce hysteresis loss..
>     That is a Loss.

Those losses are embodied as ESR. I was speaking of wires 
sufficiently far away from ferromagnetic materials so as to be 
insignificant. Furthermore, I have measured the losses and 
compared the wires about which I am speaking. All were run by 
exaclty the same route (one at a time) and all were the same length 
(17' +- 1").

> When resistence (as it always) is present,
>     by changing the power factor,
>     (I^2)*R losses can be effected.
> 
> Anyway, I was thinking about Voltage Drop,
>     not Power Loss!...Unless maybe I
>     expressed myself sloppily.
> 
> Strange that no one commented on the
>     fact that smaller diameter [straight] wires
>     have higher intrinsic inductance than
>     larger diameter [straight] wires...
>     This is not to be confused with the loop
>     inductance in coils...

I compared the losses (I am talking about in-circuit Q) of a number 
of wires. Believe it or not, solid wire with a much smaller cross-
sectional area than stranded actually performed better regardless of 
the comparative inductance. 

> > We are talking about losses and
> > therefore resistance. All else being equal, stranded wire is
> > measureably lossier than solid section, presumably due to skin
> > effect artifacts. I have measured this in quite short lengths of wire.
> > Area for area, litz is better than both as it has a greater effective
> > cross sectional area due to the insulation between strands. I am not
> > saying that a resonator built with stranded wire will produce inferior
> > results however - primary losses and output spark losses are
> > dominant.
> 
> The 'artifacts' you refer to may in fact be
> due to the inductance effect I mentioned...
> important for RF.

But not at 60Hz I would have thought? 
My "Comparison of Wires" measurements should be in the archives 
somewhere. Test frequency was somewhere around 200kHz from 
memory.

Regards,
Malcolm