Answer / vidhya

400Hz was very common in aircraft especially during WWII
and later. It was done because transformers, motors and so
on are very much lighter than with lower frequencies like
60Hz.DC could not be easily be transformed with the
echnology then.However, modern electronics allows DC to be
converted (transformed) with
very small magnetics operating at 100kHz or higher. This
stuff trumps 400Hz. What do they do in modern aircraft?
I was basically referring to the power transmission and
distribution. DC is more efficient and uses less material,
insulation, with less loss than does poly phase AC. That's
why ultra high power transmission lines like the
pacific inter-tie are often DC these days.

Answer / varun

I think(not sure)that, a.c. systems are used only where
long transmission of power is involved.Because,
(remember)d.c. system always has supirior
characteristics,either performance of m/c's or transmission
lines(HVDC).In aircrafts there is no question of long
transmission and also they must maximise their reliability
and efficiency of the operation, hence d.c. m/c's and d.c.
transmission is preferred.

Answer / atique

dont know.

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