Computer still shuts down

[Anonymous user]

I have recently purchased two APC Back-UPS ES systems, a 550 and 750. Both are fully charged and seem to be working correctly however they are not always preventing my computer from shutting down if there is a momentary power issue. At first I though the problem was the UPS 750 so I returned it for another one but still had the same issue.
The PC I seem to be having the most problem with is a one year old Dell desktop, Studio XPS 9000 . Should a power outage occur, the UPS alarm sounds but the PC immediately cuts out and reboots; however not always. This intermittent problem seems to happen with either the 550 or the 750. In both cases the only other item plugged in is an external hard drive by Western Digital that does not draw very much power at all.
Both units are being used stand alone, in other words I only have the AC line plugged into the UPS, no special software is installed and there is no other communications between the UPS and PC.
Any ideas as to what is causing the problem would be appreciated.
Thanks,
John

[Anonymous user]

I can't tell if the external hard drive is cutting out as well. The monitors are plugged into a one of the UPS systems and the PC into the other. These power interruptions are very small, my guess is a second or less, so while I lose the display of the monitor I can not tell if it is actually losing power. If I unplug the UPS for the monitors they stay on. Both UPS systems are on the same fuse circuit. My main concern is protecting the PC and not losing my work.
Not sure this is helping. Where to look next? Thanks for your help,
John

[BillP]

Does the external hard drive reboots as well or is it just the XPS PC? How about your Monitor, does it reboot itself as well?

[BillP]

Alright, so it's the XPS alone that is attached on this UPS. I assume that you it installed on the Battery side of the UPS. When you unplug the UPS and let it run on battery, does the XPS turns off and starts back up again or does it remain on off state? Is there a possibility to use/add a different load on the UPS to see if that load would drop or reboot as well?

If the UPS is on battery and the XPS has rebooted already, does the XPS stays on? If the PC reboots and stays on while it is on battery, a reason why it does this is due to the transfer time.

Here are some APC Knowledge Base Articles that I hope could help you out.

Article Link: [Equipment connected to a Back-UPS product turns off unexpectedly and/or reboots.|http://nam-en.apc.com/app/answers/detail/a_id/20/kw/drop%20load]

Article Link: [Computers containing PFC (Power Factor Corrected) power supplies and their use with Back-UPS or Smart-UPS SC UPS.|http://nam-en.apc.com/app/answers/detail/a_id/8883/kw/drop%20load]

[Anonymous user]

This is getting more confusing.
My PC and external hard drive are connected to the battery portion of the 550 UPS. To test, I saved my work and then rebooted the computer.
With the computer rebooted I unpluged the UPS, sure enough the PC cut out. It appeared that the HD continued but the light soon went out, mind you I don't believe it lost power as this is connected via USB to the PC, with the PC off the HD shuts off.
The alarm continued to sound on the ES 550 so I plugged in a 60 watt utility light into the unit to see if it was functioning on battery and it was. Now for the very odd thing, when I turned on the light, the computer restarted.....please note the UPS was still unplugged and the alarm was sounding.
Thank you for the articles however I am not sure if the powers supply in the PC is PFC and if it was should the 550 not provide enough power?
I checked the event view of the PC, Windows 7, and it showed a critical error, event 41, task 63, source Kernel-power.
I am a little stumped.
I could try this with the ES 750 but my guess is I will get the same result?
Any ideas?
Thanks again, John

[Anonymous user]

Sorry for any confusion.
The UPS, is an ES-550 purchased a few weeks ago; however I also have an ES-750 that I get the same results. Both are fully charged.
My PC and external hard drive are plugged into the battery backed up side of the ES-550. The external drive is connected to the PC via USB. My concern in determining if the external drive is being affected by the UPS is that it will be affected by the USB connection to the PC. When the PC shuts down it will turn off the external drive.
Thus I did these test with a 60 watt light plugged in the battery backed up side of the UPS.
When power is removed from the UPS, the PC shuts down but the light stays on. When power is restored to the UPS the computer reboots.
What I experienced earlier is when the UPS was unplugged and the PC shut off, when I plugged in the light into the UPS the computer rebooted, which is what I found very odd. It was like the load to the light caused the PC to reboot.
I am starting to suspect a problem with the power supply of the PC but it seems to be running fine.
Please let me know if I have answered your questions.
Thank you

Message was edited by: jlemme

[Anonymous user]

I think I may have found others with the same problem,
check this thread,
https://community.se.com/t5/APC-UPS-for-Home-and-Office-Forum/bd-p/home-office-forum

What do you think? Is the issue the pure sine wave?

[BillP]

jlemme wrote:
When power is removed from the UPS, the PC shuts down but the light stays on. When power is restored to the UPS the computer reboots.
What I experienced earlier is when the UPS was unplugged and the PC shut off, when I plugged in the light into the UPS the computer rebooted, which is what I found very odd. It was like the load to the light caused the PC to reboot.

You've said that when you removed the power from the UPS, the PC shuts down. Was it an immediate shutdown/ drop load or was it a graceful shutdown? Normally, the PC would reboot once power is restored is if you have it configured on the BIOS settings.

Some issues that I have seen when it comes to sine wave are those customers who are experiencing drop load situations when the BackUPS goes to battery. The equipment that they have does not like the waveform that is being supplied by the UPS.

[BillP · Accepted solution]

I myself got confused as well with the post above.

Let us set this straight. What UPS are you using? Where is the PC and Hard Drive connected and on what receptacles? Let us try to do the following steps:

1. Turn the UPS ON as well as the load attached to it.
2. Make sure that the UPS has been charged to 100%.
3. Unplug the UPS from the power source and let it run On Battery.
4. Do no do anything with the Hard Drive and PC, kindly observe what will happen to them once the UPS is running On Battery.
5. Let me know what would happen on the UPS and the load.
6. When you re-apply power to the UPS, observe what would happen to the load and the UPS.