krw spake thus:

In article m,
kens says...

Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

Actually, it turns out that BART is 1,000 volts DC:
http://www.bart.gov/about/history/systemfacts.asp


--
Just as McDonald's is where you go when you're hungry but don't really
care about the quality of your food, Wikipedia is where you go when
you're curious but don't really care about the quality of your knowledge.

- Matthew White's WikiWatch (http://users.erols.com/mwhite28/wikiwoo.htm)