Larry Jaques wrote:

On Wed, 6 Jul 2011 03:00:05 +0000 (UTC), David Lesher
wrote:

GeoLane at PTD dot NET GeoLane at PTD dot NET writes:


Why do they use 400 Hz for anything?

400 Hz reduces the iron needed in magnetics such as generators,
motors and transformers. Weight is a big big factor in aircraft.

Excellent. I learned my "something new every day" early today.
Thanks. I'd wondered why they used that frequency in airplanes.

Yeah, no kidding. It also allows smaller, but higher speed induction
motors. You won't believe how small a 1 Hp 22,000 RPM 400 Hz motor
is, you can just about hold it between two fingers, and easily in the palm
of your hand. Power transformers are also way smaller, if you haven't
seen the difference, you won't believe it.

Jon