This was originally posted on APC forums on 11/14/2020
I have a Smart-UPS SRT 5000 and it is reporting the wrong output frequency (58.4 Hz) while it is at 60 Hz and in phase with the utility. The frequency value is slowly decreasing with time since the beginning of 2020. The output voltage is indicated correctly. The UPS is now configured to output at 60 +/- 0.1 Hz and the bypass set to ''Phase lock Not Required'' as I was getting messages it cannot bypass.
What could be the reason for this behavior and is there something I can change to eliminate this issue.