On 05/07/2021 04:59 PM, W2HX via cctalk wrote:
I will add that aircraft are one of the main users of 400 Hz. This is because
weight is always an critical design consideration. So with smaller
transformers, smaller capacitors, etc, you can save a LOT of weight on
electronic devices in an aircraft.
73 Eugene W2HX
-----Original Message-----
From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of Andrew Back via cctalk
Sent: Wednesday, May 5, 2021 11:26 AM
To: cctalk@classiccmp.org
Subject: Re: 400 Hz
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
Interestingly, a lot of other military gear also uses 400 Hz
power for the same reasons.
I tore down a Nike radar van a long time ago, everything ran
off 400 Hz.
Jon
