Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!asuvax!anasaz!qip!john
From: john@qip.UUCP (John Moore)
Newsgroups: sci.electronics
Subject: Re: Gold saves energy.
Message-ID: <6620@qip.UUCP>
Date: 9 Jun 91 16:40:01 GMT
References: <1991Jun5.163512.1314@zoo.toronto.edu> <1987@ole.UUCP> <2943@ke4zv.UUCP>
Organization: Anasazi, Inc.  Phoenix, Az
Lines: 29

In article <2943@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes:
]In article <1987@ole.UUCP> ssave@ole.UUCP (Shailendra Save) writes:
]>
]>   Someone please verify the skin effect stuff.
]
]Skin effect is of negligable effect at power line frequencies, bulk
]conductivity still rules. If you raise the frequency to take advantage

At 60 Hz, the skin depth (where current density is reduced to 1/e of
its value at the surface) is .85 centimeters. Thus, for large conductors
it would have some effect.

]of skin effect, you start to run into radiation losses as the length of
]the conductors becomes an appreciable fraction of a wavelength. For
]typical spans, most of the electrical energy would be lost to radiation
]across only one span at less than 2 Mhz.  300/Mhz defines the wavelength
]in meters for a given frequency.

Where the current flow is balanced in a power line (normal case),
the radiation is negligible - the contributions by the conductors
cancel each other out.


-- 
John Moore HAM:NJ7E/CAP:T-Bird 381 {ames!ncar!noao!asuvax,mcdphx}!anasaz!john 
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