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Old June 8th 08, 12:44 AM posted to rec.radio.amateur.antenna
[email protected] jgboyles@aol.com is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 58
Default Efficiency and maximum power transfer

On Jun 7, 12:43�am, Owen Duffy wrote:
wrote :

...

The maximum power theorem gives conditions where power in the load, is
equal to internal power in the generator. �Not always a good idea. �A
50HZ generator capable of Megawatts of power would dissiapate 1/2 in
the generator and 1/2 in our houses if they designed them to conform
to the MPT. �The 50HZ generators would melt. �Utilities design their
Generators to have nearly 0.0 ohms internal impedance.


Actually, the AC power distribution system from alternator down has a
manged substantial equivalent source impedance.

The source impedance serves to limit fault currents, which reduces the
demands on protection devices.

Sure, the network is not operated under Jacobi MPT conditions, but neither
does it have near zero source impedance.

Owen


Not really sure I agree. A multi-megawatt 60HZ generator by necessity
has near zero source impedance. The ones I am familar with require
forced air cooling on their output buses. If you are pumping out Mega-
watts, then any non -zero source impedance results in serious heat.
I^2R.
Gary N4AST