Odd power?

[potter]

I had a power cut last night and ran my gen for the night, this morning switched over and shut down the gen.When i got back inside from shutting down i noticed my UPS was beeping not excepting line power so i got my kill-a-watt out to see what i figured might be low voltage (common on the island especially after a power cut). But the volt reading was 127.3 so shifted to hz 59.9 all normal but UPS still beeping.I played around with this for almost an hour before giving up and disconnecting and running computer without the UPS.
After lunch i tried plugging in the UPS again all is well    any ideas.I have run this system now with no changes for over 200 hrs with no problems.

  Potter

[rcavictim]

Two thoughts. 

Bullshit baffles brains.

and...

Acham's Razor: Given a curious situation the simplest explanation usually ends up being the correct one.

[Jedon]

My UPS's refuse to run off inverter power for some reason. Maybe the power company has some circuits in there... 

[rcavictim]

UPS's seem to be universally finiky about the quality of mains power that they are fed.  I have had trouble with mine on occasion trying to run them from a engine driven generator, but never off the mains as has been reported by Potter. 

Potter, there is more than just frequency and voltage as determined by some voltmeter you used.  Different voltmeters will respond to true RMS, most cheap ones only give a best guess based on peak to peak and a built in measurement algorithm.  Then there is the question about what the harmonic content or purity of the power might have been after the mains service was restored.

That was most curious and hence my earlier reply.  It may have been how you were holding your mouth or the instantaneous alignment of the planets.  Who knows?   

If you have the opportunity to look at the mains waveform with an o-scope that might give further useful clues if that ever happens again.

Perhaps if there was noise on the line a low pass hash filter could be obtained and installed between the mains power and the UPS input.

Oh and speaking of UPS input?  You guys are doing a bang up job!  You manage to bang up everything you touch. 

[dubbleUJay]

We had a telecoms outstation that keep on blowing power-supplies on various equipment intermittently with no apparent sequence.
We had to proof to the utility that it was their fault. Had to use a recorder/meter of a couple of $K to get this done!
Turned out to be a voltage spike of +2kV for a few milliseconds every 2 weeks or so!
Never found out what the problem was, it just magically disappeared after we showed them the printout, the eFFers!

Another one:
Long time ago on the "Farm-lines" (Open 2-wire party telephone lines) some nights everyone's instruments started ringing! Ringing current was +/- 75Vac@75hz at that time.
Turned out to be a cracked insulator out in the veld (open land) on a nearby power line that arced when it got a bit wet from dew early in the mornings!!! Was only found because someone was driving by at that specific time of night and saw it!

Model of the story: There's a lot of $h!t out there that we don't know about! 

[mobile_bob]

you might look up the documentation for your ups
that beeping might be a "beep code" which you can decipher and find out
what the problem is.
sometimes in conjunction with a light flash code

also i notice the apc units have a power quality set point, you use a small pointy object like a ballpoint pen
to depress a momentary swith on the back of the unit to set the thing to accept three levels of power quality
from very tight to moderately loose you set by the intensity of the accompanying green led that is located
right next to the momentary switch.

maybe you ups has something similar?

bob g

[rcavictim]

you might look up the documentation for your ups
that beeping might be a "beep code" which you can decipher and find out
what the problem is.
sometimes in conjunction with a light flash code

also i notice the apc units have a power quality set point, you use a small pointy object like a ballpoint pen
to depress a momentary swith on the back of the unit to set the thing to accept three levels of power quality
from very tight to moderately loose you set by the intensity of the accompanying green led that is located
right next to the momentary switch.

maybe you ups has something similar?

bob g

Bob, you are a wealth of knowledge.  Many UPS's, especially the larger and more useful to us here ones fall into our hands without documentation.  I have never seen manuals for any of mine.

[Tom T]

I have seen ups's that after goning on battery for a while then the power comes back have to be reset some of them are this way so you will know there was a problem. T

[potter]

Well another power cut Early this morning , it is the line power Kill-a-watt still reads good but this time I started the gen and the UPS accepted it fine switch back to line it rejects it. The first day this only lasted about two hours and then stabilised all i can do is hope.
  POtter

[Rom]

Hey Potter,

I made it back yesterday afternoon from Nassau.

This morning when I made the switch back to mains, all 4 off my apc ups were clicking on and off, cycling the relay. On generator power now for this new cut, and they have all stopped. I suppose BEC is giving us something the UPS' dont like.

[potter]

Yep try and tell them that .
 
  Potter