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"Joe Gwinn" wrote in message
news:
vnsdhi9pb0j7kvp7d1hbst7khsnboikhc4@4ax.com...
Airplanes used 400 Hz because 400 Hz transformers are a fraction the
size and weight of that at 60 Hz.
---------------------------
I was looking for why they settled on that particular number. A friend who
worked in advanced aerospace at [...] researched aircraft 28V DC and found
that it had been chosen due to a discredited idea about corona discharge
leakage at the low pressure of high altitude.
One source mentioned that iron losses increased rapidly as frequency rose
above 400Hz. I tried higher frequency AC in a small Variac core to test it
for a speaker crossover filter and found the losses quite high at 400Hz. It
had clearly been value-engineered for 60Hz but not much higher.
https://www.powerstream.com/400hz-tutorial.htm
"Boeing 787 and Airbus A380
These modern aircraft have opted to do without the alternator speed
regulator required to keep the frequency stable. Therefore their frequencies
extend from about 360 Hz to 800 Hz depending on the speed of the engines."
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