Its all in the timing, if one PS is not working and the other loses power at the same time, the system will power off. if you are having a quick power blip, you should be fine. What I suggest is to swap the power to the supplies, so that the APC power is connected to PS2 instead of #1. If the blip happens to #2 after that, you know its not the power supply, but the power itself coming into the system. if the problem continues with #1, you could try flipping PS1 to where PS2 is just to rule out a system board problem. Its all about process of elimination. On a side note, it may be worth testing your UPS, simulate a power loss to the UPS and see what happens, does the system continue to run, do the logs show a blip etc. be sure to do the testing during a non-critical time just in case the system powers off. It is also suggested that the power supplies have different sources of power, in that you dont want the system to have power from just one source. ideally, you would have 2 separate power sources coming into your building, 2 separate UPSs, one to each power supply, but this depends on how critical it is that your systems stay running. O, and you can also swap power supplies between systems to see if the problem follows the power supply. 
Hello, We own an R510 with two PS's installed, Open Manage 6.2.0 installed.   About two months ago, we got an alert from the system (OM alert) that our Power Supply Redundancy was lost.  Investigating in OM, on the Power Supply page I see that it shows Attribute: Redundancy Status as "Lost". However, looking at the Individual Power Supply Elements, both PS's show as "green check marks", and Status of "Presence Detected".    There's no indication which PS is having issues.  So at the time, I simply pulled one out, and reseated it.  After doing so, the Redundancy Status came back as green again. I chalked this up to a fluke. Last night, the same issue occurred, and this morning I'm looking at OM with the same situation of "Redundancy Lost" but both PS's showing green.   Is there any other way to determine if I'm having a true PS issue, or if there's a problem at all?  Has anyone else seen this behavior? I'm concerned that there is an issue with one of the PS's but it's transient...it would be nice to rule that out, and then if both are fine, determine why this false positive keeps occuring.   Thanks for any assistance anyone can provide.
Open Manage reports Power Supply Redundancy lost