APC BK600EI - Manual (Page 22)

Page 20
Option
Switch #2
Option
Switch #3
Undervoltage
Transfer
Down (OFF) Down (OFF) 196 Vac
Up (ON) Down (OFF) 184 Vac
Down (OFF) Up (ON) 172 Vac
Up (ON) Up (ON) 160 Vac
5.4.3 Option Switch #4
Option switch #4 sets the internal operating frequency of the inverter. It should be set to
match the local line frequency. When in the down (off) position, the UPS will operate
properly with a 50 Hz line. If your local line frequency is 60 Hz, set the option switch #4
in the up (On) position.