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Re: Top Terminal Shape

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>


> Date:          Thu, 22 May 1997 08:14:45 -0500
> From:          Tesla List <tesla-at-stic-dot-net>
> To:            "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
> Cc:            "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
> Subject:       Re: Top Terminal Shape

> Subject:  Re: Top Terminal Shape
>   Date:   Thu, 22 May 1997 01:24:44 +0500
>   From:  "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com> 
>    To:   Tesla List <tesla-at-pupman-dot-com>
> 
> 
> On Wed, 21 May 1997 14:24:36 -0500 Robert W. Stephens
> <rwstephens-at-headwaters-dot-com> wrote;
> 
> > Alfred, All,
> > 
> > Quite some time ago there was a list discussion about how various 
> > types of flat strap, tubing, solid wire, twisted multi-strand wire,
> > straight multi-strand wire, and braided wire (like the outside jacket
> > of coax or the flattened braided strap), all compared to each other.
> > Richard Quick and Malcolm Watts in particular gave an enormous
> > 'thumbs down'on the use of braided conductors in our RF application
> > of primary coils and ground runs.  Seems the electricity has to hop 
> > between all those little wires while doing the skin effect dance.  
> > The braid is not laboratory clean and there is some junction loss at 
> > each connection.
> 
> I remember seeing some comments to that effect in the archives to 
> this list and USA-TESLA, that is why I was surprised when someone on 
> this list stated they had good results with Litz wire, it seeed to 
> conflict those findings.
> 
> > My usage of the term 'illegal' was merely tounge-in-cheek.
>  
> That is what I thought but I figured I would ask just to make sure.
> 
>                                Sincerely
> 

> 
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 
large CW, vacuum 
tube TC employed to swing a large top C (hundreds of picofarads to 
even 1000 or more) in a test room to several 
hundreds of kV's will benefit from the use of Litz as the average RF
amperes
throught the secondary resonator will easily become 25 to 100+
continuous 
average amperes.  At DC a beefy 10 guage wire secondary will quickly 
warm at such continuous currents. At RF the actively employed cross 
section would make less of that #10 wire active, and a meltdown would 
be imminent.  Long before the wire melts its insulation or the coil form 
may be severely melted, deformed or otherwise heat damaged.  Litz 
wire the same overall diameter as the solid #10 could run cool in its 
place.  

A disruptive TC making enormous streamers even at 20 kVA average input
levels
and multi-megawatt peak pulse energy levels (but extremely low duty
cycle)
can do so without detectable secondary winding heating employing just
about
any old kind of insulated and modest gauge wire.  Cool! : )

rwstephens