Powerware 9330 Installation And Operation Manual page 84

If the input power fails to return or is not within the acceptance windows required
for normal operation, the battery will continue discharging until a DC voltage level is
reached where the inverter output can no longer support the connected loads.
When this occurs, the unit will issue another set of audible and visual alarms
indicating SHUTDOWN IMMINENT. Unless the rectifier has a valid input soon, the
output will only be supported for 2 minutes before the output of the system shuts
down. If the bypass source is available, the system will transfer to Bypass instead
of shuting down.
If at any time during the battery discharge the input power becomes available
again, contactors K1 and K5 are closed and the rectifier will begin to supply DC
current to the boost converter and inverter. The battery contactor K2 is opened
while the battery charger is turned back on to begin recharging the battery. At this
point, the unit returns to normal operation. Depending on the amount of load on
the system and the duration of the battery discharge, battery current limit alarms
may be seen for a short time due to the current required to recharge the battery.
The systems total operating time on battery will depend on many factors. Some
factors that affect battery support times are battery type and capacity, number of
parallel strings, environmental temperatures, age of the battery, and fluctuations in
load demand during the discharge. The greater the load, the less support time the
battery will have. Decrease the load, and the battery support time will generally
increase.
Powerware 9330 (10 kVA- -40 kVA) Installation and Operation
6--10
164201300 REV. G 061502