Battery Mode; Figure 5. Path Of Current Through The Ups In Battery Mode - Powerware 9315 Operation Manual

Battery Mode

The UPS transfers to Battery mode automatically if a utility power outage occurs, or
if the utility power does not conform to specified parameters. In Battery mode, the
battery provides emergency DC power that the inverter converts to AC power.
When the UPS switches to Battery mode, the alarm indications depend on the
cause and condition of the battery charge. The length of time the system can
operate in Battery mode depends on loading and the battery supply capacity.
Figure 5 shows the path of electrical power through the UPS when operating in Battery
mode.
Bypass
Input
Rectifier
Input
Path of electrical power
When the discharging battery voltage reaches the lower limit of UPS operation
capability, the critical load transfers to Bypass mode if it is available. If Bypass input
is not available, a "Shutdown Imminent" warning occurs. The warning time before
critical load loss occurs is approximately 2 minutes, depending on battery capacity
and the amount of loading.
If incoming power returns to within specified parameters, the UPS automatically
returns to Normal mode and alarm indications clear. However, the process of returning
to Normal mode is not instantaneous. The rectifier gradually draws increasing power
from the incoming utility until Normal mode is achieved.
12
RECTIFIER
CB1

Figure 5. Path of Current Through the UPS in Battery Mode

BYPASS
K4
INVERTER
BATTERY
Powerware 9315 (200 kVA ---300 kVA) Operation
Output
K3
(closed)
TRANSFORMER
164201036 Rev. D 041500