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I came across an article where it mentioned that aircraft systems operates at 115VAC @ 400Hz. The reason cited (but not explained in detail) was related to reduction in weight of power supplies.

My question to experts of this forum is, does frequency have a bearing on the size of power supply designs? Can you please suggest me a link for some further reading?

Regards,
Ritika

I think you are correct the power to weight ratio is much higher at 400 Hz because the motor can be up to 24,000 RPM. I recently installed a 400 Hz well pump about 1.8" in diameter that pumped at an amazing rate.
http://www.dicore.cl/409.pdf

I have also seen 400 Hz power tools. BTW, lots of VFDs will give you 400 Hz suitable for this type of motor.

Roy

Hi,

When the frequency is high, the sizes of transformers, inductors and capacitors used in the system becomes smaller. The same we can say for motors, the size will be smaller, but the torque rating would go down because of higher RPM.

Also for lighting it will reduce the sizes of the components used.

There may be more explanations...

mbarazeen at yahoo. com

At 400hz, any filtering for DC supplies becomes much easier than at 60 HZ. Component values are smaller and you don't need those huge chokes that were common before the advent of switching power supplies.

As the frequency increases, the iron needed in the magnetic circuits decreases. This saves weight and space in transformers, motors, relays and actuators.

As the frequency increases, the arcing in the brush increases and quenching that arc is also difficult, so due to this and brush design becomes difficult.

The brush drop at low frequency is also high compared to high frequency.

Gowrish,

I don't think most 400 Hz motors would have brushes, just 3 phase squirrel cage. Because of the high speed they develope more HP for a given frame size.

Roy