APC Backup RS 1200 Failure

[Anonymous user]

We use APC RS 1200 as power backups for cash registers at our business. 11 APC RS 1200s for 11 registers. Yesterday we had a storm pass through and had a very brief power failure. Basically power was cut for a second or two, some lights flickered, then it passed.

Our problem is that three of the cash registers did not immediately go to battery backup and rebooted themselves.

Afterward, I checked to make sure that all the necessary components were plugged into the appropriate plugs, and not the surge-only plugs. I pulled the power to the batteries and there was no interruption to the register power. They ran for several minutes only on the batteries. They display no warning lights indicating that the battery is bad or going bad.

These RS 1200s are less than two years old and I am told are still under warranty.

My question is are these defective units? What can we do to prevent this from happening in the future?

[Anonymous user]

Very interesting, thanks for the help!

[BillP]

did the UPS reboot as well or turn off itself? i have heard of this sometimes. the transfer time to and from battery is 4-6ms on these units. sometimes with power glitches stuff like this can happen with relay and the transfer.

i dont think the unit is faulty and i think replacements may do the same thing in a similar scenario because of the transfer time and type of UPS topology.

:/

[Anonymous user]

Thank you for the answer.

I am not aware the the UPS's rebooted or that they didn't either They remained active after the fact so I certainly wouldn't rule it out. The power cut was very brief as I mentioned, some lights flickered, etc. The power cut may have been too short to initiate a proper transfer to the battery but enough to reboot the machines, if that's a possibilty

But obviously with an electrical event of this nature minor seeming is not always necessarily minor. Would a powerful enough surge cause some sort of protective reboot of the UPS device?

[BillP · Accepted solution]

no, if anything, a surge would attempt to be shunted to ground, then absorbed by MOVs, fast acting fuses, and thermal fuses.

it should catch any minor blip really but there may be a scenario where the UPSs decision is tough and then we are talking about mechanical parts taking time to move, etc

it really sounds like some type of transfer time issue with whatever happened in this particular scenario where the UPS had to decide what to do and if the registers are sensitive enough, the UPS may have taken too long (more than 6ms) to switch to battery so they lost power.