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UPS AC output problem

APC UPS for Home and Office Forum

Schneider Electric support forum for our APC offers including Home Office UPS, Surge Protectors, UTS, software and services and associated products designed to share knowledge, installation, and configuration.

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BillP
Administrator Administrator
Administrator
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6
234

UPS AC output problem

This question was originally posted by michael on APC forums on 1/15/2008


Hello,

i have the ups model APC BK650MI and i have the following problem,
when the Ups is on AC power the output is 220 Volts (Thats ok) but
when i disconnect AC power output drops toy 170 Volts.
The battery of the ups is new and checked.
Does this problem means that i have electronic problem ?

Please help ...


Accepted Solutions
Rose_lose_apc
Crewman
Crewman
0 Likes
0
236

Re: UPS AC output problem

This was originally posted on APC forums on 5/21/2018


Yes this unit dropping load when battery power. What should I do now?

See Answer In Context

6 Replies 6
shindvs_apc
Ensign
Ensign
0 Likes
0
236

Re: UPS AC output problem

This was originally posted on APC forums on 5/6/2008


Hi
Can I talk You directly?
shindvs@gmail.com

KVAr_apc
Captain
Captain
0 Likes
0
236

Re: UPS AC output problem

This was originally posted on APC forums on 1/16/2008


infrared wrote:
I measure the voltage with a voltmeter (NOT true RMS). When the Ups is on the ac voltmeter says 226 volts witch is OK but when i plug of the AC (ups is on battery ) then
volts are dropped to 170 volts (having or not load on the ups). If i have load then the connected device (a simple PC for example) turns of immediately when AC power disconnects
I open UPS and i measure the battery and its says 13.7 volts and i think is OK besides the battery is 2 days old.
Is this normal ?
Yes, the voltage reading is normal. You're reading 226v on AC power, because it's sinusoidal. You're reading 170v on meter, because the meter can't properly read the modified squarewave.

It's not normal that your PC shuts off when you disconnect the AC to UPS. Does the UPS shut off as well?

BillP
Administrator Administrator
Administrator
0 Likes
0
236

Re: UPS AC output problem

This reply was originally posted by michael on APC forums on 1/16/2008


I measure the voltage with a voltmeter (NOT true RMS). When the Ups is on the ac voltmeter says 226 volts witch is OK but when i plug of the AC (ups is on battery ) then
volts are dropped to 170 volts (having or not load on the ups). If i have load then the connected device (a simple PC for example) turns of immediately when AC power disconnects
I open UPS and i measure the battery and its says 13.7 volts and i think is OK besides the battery is 2 days old.
Is this normal ?

Cap1_apc
Lt. Commander
Lt. Commander
0 Likes
0
236

Re: UPS AC output problem

This was originally posted on APC forums on 1/15/2008


Infrared,

How are you measuring the output? This unit will output a stepped approximated sine wave when on battery power. You will need a true RMS voltmeter to get an accurate reading of the voltage here.

Does the unit drop the load when on battery power?

You definitely want to read into kbase 1493:
http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=1493&p_created=1010390400&p...

null

KVAr_apc
Captain
Captain
0 Likes
0
234

Re: UPS AC output problem

This was originally posted on APC forums on 1/16/2008


The power quality from that and many other consumer UPSs isn't anywhere near as good as the main line. The output on UPSs are almost always modified square wave unless otherwise stated.

To measure the voltage on a modified squarewave inverters and UPSs, you'll need a True RMS meter. Not advocating for one brand, but an example is the Fluke 87 series. Multimeters are almost always "typical responding" or not true RMS. True RMS is a feature most meter manufacture would make sure to get printed on the front cover.

Rose_lose_apc
Crewman
Crewman
0 Likes
0
237

Re: UPS AC output problem

This was originally posted on APC forums on 5/21/2018


Yes this unit dropping load when battery power. What should I do now?