Franc Zabkar writes:

On Tue, 14 Oct 2008 17:35:17 -0400, greenpjs put
finger to keyboard and composed:

On Tue, 14 Oct 2008 13:15:28 -0700 (PDT), z
wrote:

On Oct 12, 7:32*pm, Steve wrote:
I am building a piece of equipment for the aircraft industry that uses
a 115V 400Hz electrical supply. * I have found I need to fit a cooling
fan (like a PC one but a bit wider - about 5 inches diameter) and have
got a 120V 50/60Hz one.
Will this work? *Impedance wise a higher frequency would mean less
current drawn by what is presumably a mainly inductive load, but my
main query is are fan rotation speeds related to the AC supply
frequency? *If so I guess trying to run a fan at about 7 times it's
rated speed would not be a good idea so I haven't yet tried it.

i'm pretty sure a 50/60 cycle fan wouldn't work; i agree with the guy
who suggested a DC one. plenty of DC muffin fans around, and DC is
universally producable. on the other hand, i don't know anything about
airplane equipment, although i still have an old war surplus 400 hz
motor/generator knocking around somewhere.
I once ran some ham equipment (which used a linear 12v power supply)
from a 400 Hz surplus generator. It worked well. The only way I
could tell was instead of hearing a slight 60 Hz hum in the receive
audio, I heard a slight 400 Hz hum. I felt like I was listening to
flight attendant announcements in a DC-9. To this day, the PA system
in DC-9's have that hum. By "to this day", I mean flying in an
AirTran Boeing 717 which was the final configuration of the DC-9
before they went out of production. Sorry. Just rambling... None
of this has anything to do with running an AC fan.

While we're rambling, I wonder how a mains frequency digital flip
clock would run on a 400Hz supply, assuming it survived the
experience. I reckon it would make an excellent bundy clock. Here in
Australia we'd cut our working days to one hour ... just enough time
for lunch. Time would fly.

These are synchronous motor-driven.

Better to hack a digital clock.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.