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Re: [RFI] Power Lines

To: "Gary \"Joe\" Mayfield" <gary_mayfield@hotmail.com>,"'Jim Miller'" <JimMiller@STL-OnLine.Net>, <rfi@contesting.com>
Subject: Re: [RFI] Power Lines
From: "Jim P" <jvpoll@dallas.net>
Date: Sun, 23 Dec 2007 13:37:50 -0600
List-post: <mailto:rfi@contesting.com>
Just an observation - and somebody correct me 
if I'm wrong ..

>From what I have read and studied on power 
generation, power transmission and power 
distribution, the power companies extend out from 
the central (generating) station to the various sub- 
(step-down) stations all three phases of generated 
voltages from the generator (speaking of AC 
systems now! And I'm not addressing an inter-tied 
tructure as the present 'power grid' is built and 
operated either.).

This would seem to be done for several reasons, 
not the least of which is, three phase power generation 
provides for a more equal 'torque-loading' (on 
account of the sinusoidal function involved when 
a wire is rotated in a circle and made to 'cut' through
magnetic lines of force) of the generator's armature 
than a single phase would, and this also translates 
out into the user segment of the system when higher 
amounts of power (e.g industrial users and greater 
amounts of torque as say provided by three-phase 
motors) is required. 

It also seems that the power companies further 
extend three phase distribution lines out into the 
area to be served also for the purpose of being 
able to load-balance all three phases; single phase 
business and residential 'user' loads can easily 
be swung from a more heavily loaded phase, 
for instance, to a less loaded phase as an area 
develops or gets built-out. At some point, out 
towards the 'edge' of a service area single phase 
distribution lines begin to appear (we used to have
an old REA line running along side one of our
major secondary roads about 10 years back, but that 
'line' has upgraded to all three phases now!)

So, it is this generation/transmission/distribution of 
all three phases would appear to the be basis for 
the "divisable by three" rule.

Caveat: All this is the result of observation and some 
self-paced study as I have never worked for, or worked
in, the power generation or power transmission or 
power distribution industries.

Jim P // WB5WPA //

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