Re: skin depth

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

There are also other effects such as surface oxidation and proximity 
effects in real situations that are probably more important.  Medhurst and 
many others of studied this.  In general, people use skin depth as an 
approximation or guide rather than a high accuracy absolute number.  When 
one "attempts" to get down to such high levels of accuracy, the 
complications become horrific.  There are are many papers and such on the 
subject.  However, for our uses, knowing skin depth to high accuracy is not 
a concern.  We just have to understand the general idea to avoid obvious 
gross problems.

Skin depth usually is not a concern if you don't use magnetic materials and 
the RMS currents are reasonable.  With say 500 amps CW at 60MHz, skin depth 
problems are easy to find since the offending part bursts into 
flames.  With a little practice, one learns the best materials to use and 
why "quickly".  Skin depth is a concern,but high accuracy is not.

Cheers,

         Terry

At 05:15 PM 9/23/2003 -0700, you wrote:
>Tesla list wrote:
> >
> > Original poster: Peter Lawrence <Peter.Lawrence-at-Sun.COM>
> >
> > I still find it very odd that apparently no one has done skin depth calcs
> > for cylindrical wire, only for hypothetical infinitely wide infinitely deep
> > flat plane conductors...
> >
> > Sounds like a good problem for a math-physics type, or even a
> > physical-simulation type.
> >
> > -Pete Lawrence.
>
>         I suspect that was worked out at least 80 years ago.  Remember 
> that if
>the skin depty is a small fraction of the circumference of the conductor
>it will be the same as for a flat plate.
>
>Ed