UPS, High Input Voltage

[JSK]

I have a UPS that is very sensitive to voltage and it's triggering alarms when voltage fluctuates and hitting 127 VAC. When it's below 126 VAC it's okay no issues. The unit is pluged on a dedicated 30A 1Ph twist lock receptacle, 30A breaker.

Is there a voltage regulator/conditioner that I can add to the panel that can maintain a continuous 120VAC or maybe just for this 30A breaker feeding the UPS.

 

[zbang]

An alarm is raised when the input voltage rises above 127, yes? Depending on the UPS, there may be a a setting for this, it's always wise to ask the manufacturer about this kind of thing. (What make/model is it? That's usually useful.) That aside, I wouldn't call it "very" sensitive to 5% over nominal. If the line voltage is sitting up there, use a buck transformer to drop it into range. If it's jumping around and spiking then maybe there's a system problem, I'd go back to the UPS maker with some data and ask them.

 

[JSK]

The unit is a APC Smart-UPS X 2200 Va.,
I did call the manufacturer and said the input is capable of handling (AVR) 100-127 VAC.
My panel voltage fluctuates from 122-127VAC, so when it see 127V it triggers an alarm, it does not have an option where I can adjust the max voltage alarm since it is a smart UPS.

 

[zbang]

Where are the alarms appearing, in PowerChute, via SNMP, or just on the front panel? A quick google search for "UPS Compensating for high input voltage" turned up a lot of answers. Have you read the UPS manual?

As the line is running high-ish anyway, is there a transformer you can re-tap to drop the voltage? Otherwise a boost/buck transformer will do the job but if the only problem is excess alarms I'd be inclined to ignore them.

 

[JSK]

It's just an high voltage input alarm causing the issue and we don't really want to shut the alarms off as they are important incase any power failure etc. In this case I thought it would be easy to see if there is a voltage stabalizer that I can add to this circuit as it's not a big voltage spike. Not sure if the main transformer has other other voltage taps, I would have to look into that. Thanks!

 

[zbang]

Remember that the UPS is a voltage stabilizer, but it can only do so much.

 

[hbiss]

Remember that the UPS is a voltage stabilizer, but it can only do so much.

Well, not that one. All it is is an ATS that transfers over to an inverter (or alarms) when it doesn't like the power. The range seems rather narrow with an input spec'd as 120-125 volts. No matter what you do you are going to have problems IMO. Seems to me that it should be user adjustable.

Never liked APC.

-Hal

 

[ruxton.stanislaw]

Not suggesting it, but maybe a bodge resistor could help. Or disable the piezo buzzer; it still continues to function correctly otherwise, right? 127 V is totally normal these days. My last apartment in Canada had 128 V nominal peak (they run the three phase a bit high to reach 220 V L-L).

 

[DZ_EE]

You might also check with the utility to see if their service point voltage is getting too high. Or an internal transformer could have a no load tap that is set to something other than nominal voltage.

 

[retirede]

The ANSI spec for utility voltage tolerance is 5%. Which just happens to be 126V on the high end. I’d bet APC used this to determine the overvoltage alarm setting of 127.

 

[hbiss]

Also consider that most computers and switch mode power supplies will work with 100 to 240V so it seems silly for a UPS to brick wall at 126V and switch to backup below 120.

Never liked APC. Wonder if they still cook the battery with Li-ion like they did with the gel cells.

-Hal