UPS giving high AC frequency?

[dtemp]

I have a APC BackUPS ES 750 UPS. When unplugged and supplying my server with battery power, I noticed an unusual hum coming from my server's PSU. Figuring the voltage was screwy or something, I prodded it with my multimeter. Turns out the voltage is ok (113VAC), but the frequency is bad! Instead of 60Hz, its 300Hz!

So, will this screw up my PSU and anything attached to it? I mean the PSU ran on it for 15 min or so, and everything works, but is this something to be avoided? Is it normal to have a UPS give high AC frequency while on battery?

 

[505090]

Perhaps your meter isn't on the right settings that is a rather large variance. Test a wall outlet and see what you are getting for volt / hertz.

 

[dtemp]

Meter is fine, outlets say 59.80Hz.

 

[RetiredChief]

Short Answer - Yes. Do not use UPS. High Freq is not recommended for Transformers designed for 50/60 Hz input. (1) input impeadance is 5x higher and the insulation dielectric is coniderably reduced which could cause interwiring arcing. Also not good for motors. 300 Hz is great for direct conversion (no xformer) to DC as it is much easier to filter. Also works great on electric soldering iron, although they do not last long and your toaster could toast your bread much faster. Aircraft electronics are often designed to run on 400 Hz as it reduces the size/weight of transformers and filter caps.