Jerry Irvine wrote in news: snipped-for-privacy@news.verizon.net:
Do you mean the laser converting only 10% of the input energy to actual laser output,or that the generators being driven from the PTO are only 10% efficient?
Shuttle SRBs in the news
Oct 24, 2003
46 Replies
Chuck Stewart wrote in news: snipped-for-privacy@anapuma.nekolabs.edu:
So,they are going to install a MEGAWATT generator to be driven by the turbine? Think about that for a moment.How big would a MEGAWATT generator be? How much is that going to weigh? Is it a superconducting generator? How big is a MEGAWATT generator in a powerplant here on Earth,like the ones that supply your home electricity?
End to end.
Well, it looks like a typical unit designed to operate at
1800 RPM with 1 MW (1000 kW) of 60 Hz power output in a stationary diesel generator set weighs about 6400 lb. and is roughly 5 ft. long and 2.5 ft. in diameter.(This is for the generator itself - the complete diesel set including the engine is, of course, larger.)
A generator designed to power an airborne laser with mechanical input from a turbine engine could well be designed to operate at higher RPM and frequency, and therefore might be more compact and lighter than one intended for stationary diesel-powered operation at 60 Hz... a higher output frequency would be no disadvantage in an application where the output quite likely will be rectified to DC in any case.
-dave w
90% is a good starting point for the efficiency of generators. There are better and worse, but 90's a good round number.
Doug
I can't pinpoint the physical size, but to put it in perspective, 1HP is
746 watts, so 1MW = 1000000/746 = 1346HP. Two Winston Cup motors can do this. IE, a couple of small block Chevys.Doug
And a 1MW source is much smaller for a short duty cycle load like a pulsed laser.
-John DeMar
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