400 Hz

[Andrew Back]

On 05/05/2021 16:07, Grant Taylor via cctalk wrote:

> Were the higher frequencies used because it directly effected the amount
> of time / duration in (fractions of) seconds between peaks of rectified
> (but not yet smoothed) power?

Haven't read the rest of the thread and so at the risk of being
profoundly wrong... Benefit of 400Hz mains is that transformers can be
much smaller. Think of switching power supplies that rectify to DC and
then switch up into kHz, which are then able to use far smaller
transformer cores than an old linear PSU. At least this is a key
motivation with 115V/400Hz 3-phase aviation power AFAIK.

By coincidence we've just built a big 28VDC power supply, so that we can
run a vintage 400Hz aircraft rotary inverter, which will then be used to
power up old mil surplus kit that wants this. A classic adventure in yak
shaving. Anyway, here's the 28VDC bit.

https://www.rs-online.com/designspark/constructing-a-high-current-28v-dc-power-supply

Andrew