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Re: Balancing L/C Sizes



Original poster: "Michael Rhodes by way of Terry Fritz <twftesla-at-uswest-dot-net>" <rhodes-at-fnrf.science.cmu.ac.th>

For the groups' information in case it hasn't been posted here
is the relationship of frequency to skin depth.

In a copper wire at 100C, this depth (in centimeters) is 7.5/sqr(f) where
f is the frequency in Hz.  Don't know what it is at other temperatures,
perhaps
someone out their can let  us know.  The following is a table of frequencies
appropriate for TC work.

Table 1-Skin-effect penetration depth
Frequency(kHz)    Depth(cm X 10-3)   AWG gauge
50                          33.5                         27
100                        23.7                         31
200                        16.8                         33
300                        13.7                         35
400                        11.9                         36
500                        10.6                         38
750                        8.7                           39

So if you take the radius (not diameter) of #22 AWG wire (.032cm)
that would suggest a frequency of 55kHz before the skin effect is totally
negligible?  If I have time I'll try to write a program that correlates
the frequency with the cross sectional area that the electrons will
travel per gauge of wire.  That would reflect the current handling
capability and loses.


Found this information at
http://www.ednmag-dot-com/ednmag/reg/1999/012199/02df1.htm
while researching for losses in magnets.

Would be interested in any comments on this.

-- Michael

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, May 01, 2001 9:00 PM
Subject: Re: Balancing L/C Sizes


> Original poster: "William Swanson by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <swansontec-at-yahoo-dot-com>
>
> smaller wire does have greater losses. However, as
> somebody else pointed out, after a certain point the
> skin effect takes hold and causes the decrease in
> resistance for a given wire size to decrease only
> linearly. Once this limit is reached, wire size
> becomes unimportant, but below this limit, it is
> important. Perhaps this is the reason for the rule of
> that says you should stick with 22 gauge wire for your
> secondary...
>
> Sorry for the goof up.
>
> -William