AP7941 Error message and Local Power Supply Fault

[Anonymous user]

Hello. I recently observed an error message ("Er") on one of my PDU's model AP7941. Within a few weeks I saw the same error message on the display on another PDU of the exact same model. I have contacted APC via phone and their response was that the error message I saw was a result of a "Local Power Supply Fault". Subsequent contacts with APC via email to explain what may have caused the power supply fault yielded a respond of it being the result of a hardware failure. I was told the PDU was likely not overloaded and there really is no way to know what caused the "Er" message. What typically causes a local power supply fault in a PDU and how do I determine if that is what caused the "Er" message on my PDU?

My understanding at this time is we have not configured our PDU's to allow access into the configuration information. So I do not think I have access to any event logs.

Thank you.

[BillP · Accepted solution]

the power supplies in the PDUs control the outlet relays. we have a primary and a secondary supply so that if one fails, a secondary takes over. if we did not have a second power supply, one power supply fault would cause the relays to all fail open and drop the load.

i am not sure specifically what causes it but i assume something like a faulty capacitor or over time, the hardware could fault. i assume there is an internal check of some sort to monitor the 5vDC or something that the power supply should be outputting. generally yes, though, a power supply fault requires the PDU to be replaced.

Er can be on the screen for a power supply fault or any other fault: NMC to PDU internal comm, wrong firmware flashed on the unit, or overload. just to clarify, none of these other conditions would cause a power supply fault.

you could at least try and download the files and check them: http://nam-en.apc.com/app/answers/detail/a_id/9321