In article <4852a4fe@212.67.96.135>, Dave <foo@coo.com> wrote:
>I'm looking to use a Sun Netra T1 onboard an aircraft where the supply
>is 120 V 400 Hz
>
>The specs on the Netra T1 are:
>
>100 - 240 VAC, 47 - 63 Hz, 2 A (max)
>
>Has anyone ever tried running one at 400 Hz? My guess is that it is
>unlikely to be an issue, as the input voltage will soon be converted to
>DC in the switch mode power supply by a bridge and capacitors. A higher
>frequency should have not be an issue there, and if anything gives the
>capacitors an easier time.

Actually the most likely problem would be the bridge. High power diodes
can be quite slow (have a high stored charge) and can overheat if they
are run at a high frequency. There are fast diodes available, but they
cost more and are usually not used if not needed. This is definitely
a problem in the part of the supply where the switching is done as the
frequency there is usually over 20000 HZ. I am not sure if 400 HZ is
high enough to cause problems, but it might be.
If you try it and blow the bridge, most likely the only other thing that
will be killed would be a fuse (I assume it does have a fuse). In that
case the cost of the parts to fix it would not be very high.

>
>Dave