[Prev][Next][Index][Thread]

Re: Top Termnal/LITZ wire

Subject:       Re: Top Termnal/LITZ wire
       Date:   Mon, 26 May 1997 18:25:53 +1000
       From:   Phil Chalk <philoc-at-ozemail-dot-com.au>
Organization:  Secure_Logic
         To:   Tesla List <tesla-at-pupman-dot-com>
 References:   1


Tesla List wrote:
> 
> Subject:  Re: Top Terminal Shape
>   Date:   Sun, 25 May 1997 20:30:04 -0500
>   From:  "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
>     To:   Tesla List <tesla-at-stic-dot-net>
> 

> Alfred, All,
> 
> Litz wire is a thing entirely different altogether to braid, or multi
> stranded cable.  Each individual parallel conductor in Litz is
> separately insulated from all its neighbours.  Each strand is just
> enamel or high-tech polymer coated fine solid copper magnet wire.  At
> medium RF frequencies where Litz is most effective each strand
> operates around 100% efficient in the conductivity usage department
> where the skin depth at the operating frequency penetrates to use
> nearly the entire
> cross section of each individual strand.  Multiply this by multiples of
> many, many strands and you quickly build up an efficient copper
> conductor capable of high current, high frequency power where most or
> all of the available cross section of the copper used to make the
> cable is employed.  Applications which gain the most from Litz are in
> high power CW mode oscillator and coupling or matching coils.  At 100
> kHz a
> 

Robert, et al

Hi.  I was just about to dive in & make the same point, but it's already
been so well done, above.

I'd been thinking too of using Litz for a secondary.  I spied a big roll
of the stuff at a place I was doing some work at yesterday.  I had used
this same wire, for the same company, to make loop antennas for a
proximity access-control system, being used to detect theft of equipment
(PC's, printers, faxes etc) from a business lounge at Sydney Airport. 
These readers operated at around 140 kHz.

The wire is about 3mm dia. (just under 1/8"), and was made of three
twisted bundles of, from (vague) memory, about 270 strands each, for a
total of 800-odd (or was it 270 total?) very fine strands, double silk
covered.  It came from Germany & would have cost them a squillion.  I
didn't check it out at the time, but it looks like a good few hundred
metres left on the roll.

I thought it might make a really nice secondary, but from your comments
it seems like it wouldn't be a big, or any, improvement.  It still
sounds to me like a good choice for wiring lower-powered primary
circuits, for instance.

I think I'll still pinch a bit & parallel say 3 strands to make the
connection to the clip that taps the primary of my little (12kV/30mA)
coil.

Being a Ham & general radio-head from way back, I've always had a bit of
a thing for litz wire.

Cheers

Phil Chalk.