Symmetra PX operational safety of tests

[ojfsdi]

I inherited a PX that I was warned by the previous owner was unreliable.  It recently left our load OFFLINE! following a power outage too, see https://community.se.com/t5/Datacenter-Forum/PX-Leaving-load-offline-until-manual-startup/td-p/37259...

I want to do a UPS Self Test, and a Runtime Calibration, to exercise the unit and gain information on any faults discovered.

When I look at the diagnostic page on its web interface though, I see:

Diagnostic Tests
Self-Test:	Failed on February 24, 2018
Calibration:	Not Available on Unknown
Initiate:	UPS Self-Test Runtime Calibration

So.  It definitely failed last time it was run.  which was a log time ago.  And it left us in the dark recently.

Yet I know we've used the PX before with success to buffer power while we went on generator for a day when the utility company was doing work that took the building offline.  And since setting up logging I've gotten several notices of the UPS switching to battery and back to AC, presumably because of a momentary blink in power.

What are the chances of the Symmetra PX dropping load during a runtime calibtarion, or during a self-test?  Is one safer than the other?

If the batteries can't hold up, does it seamlessly abort the test and go to internal bypass?

For example:  If I ran a self-test, and isolated the battery cabinet at its DC breaker, would the PX be able to switch to bypass mode fast enough to avoid disruption of the load? 

[al_buffington · Accepted solution]

Hi.

The odds of dropping the load during one of these tests is remote. There is really no difference in risk between the two. The difference between the tests is related to duration and purpose. The calibration is meant to adjust the displayed runtime. The runtime value on the display requires a deep discharge of the batteries in order to update based on battery health,  For example if you had a UPS that never went to battery, or only experienced very brief outages, the runtime would display the same regardless of the age of the batteries (assuming load and # of batteries remained constant). A calibration would typically be run annually or after a full battery replacement,  It requires the charge level to be at 100% and will discharge the batteries down to 25% capacity.

The standard battery test will transfer the UPS to battery for up to one minute and is designed to check for battery faults.  If during either test the batteries are unable to support the load the UPS should transfer back to the inverter rather than transfer to bypass. 

[ojfsdi]

When you say "standard battery test", can you confirm that means the "UPS Self-Test" that is on the "Diagnostic Tests" screen?

I believe the UPS can be scheduled to perform this test autonomously every 2 weeks, which I will consider, though I'd prefer putting it on an employee calendar and having eyes on the equipment in person during the test.

[al_buffington]

Hi,

Yes, I was referring to the self test from the diag menu. You're right that the test can be automatically set to run every two weeks, but it cannot be scheduled for a specific date/time. Many users choose to run this manually so it can be run at a desired time. I hope this clears things up.