Powerware 9315s - Manual (Page 56)

7--4 Powerware 9315 Parallel Capacity/Redundant System with PHP SSBM
164201373 Rev. A 092402
7.2.1 Normal Mode
In Normal mode, utility AC power is supplied to the UPMs. Power from the output
of the UPMs is then supplied to the SSBM for parallel operation. The SSBM then
supplies the critical load with clean, filtered AC power. The message “System
Normal” appears in the status area of the Control Panel LCD screen.
Figure 7---1 shows the path of electrical power through the Parallel
Capacity/Redundant system when operating in Normal mode.
Path of Electrical Power
UPM1
UPM2
UPM3
UPM4
SS
FBP
CBP
CBS
BYPASS
INPUT
OUTPUT TO
CRITICAL
LOAD
BATT
UPM
INPUT
BATT
BATT
BATT
SSBM
(open)
Figure 7---1. Path of Current Through the Parallel Capacity/Redundant System
in Normal Mode.
If the utility AC power is interrupted or is out of specification, the UPMs
automatically switch to Battery mode to support the critical load with no
interruption. When utility power returns, the UPMs return to Normal mode.
If the UPMs becomes overloaded or unavailable, the SSBM switches to Bypass
mode. The SSBM automatically returns to Normal mode when the error condition
is cleared and system operation is restored within specified limits.