Emerson Liebert ITA User Manual page 40

32 Chapter 3 Parallel UPS Installation And Commissioning
Sharing battery strings
Using the shared battery strings in the parallel system can save investment in equipment for the users.
1. If the battery strings (four standard battery modules, option) are shared in parallel system, the backup time of the battery module
ranges from two minutes to three minutes at full load.
2. To ensure the abundant backup time of the battery, it is recommended to use the external battery cabinet with big capacity.
1. Wiring
Power off the parallel system completely, disconnect the battery MCBs of all single UPSs, and then use battery
cables (refer to 2.5 Connecting Power Cables for the cables and the MCBs) to connect '+', 'N', '-' and 'PE' terminals
of the battery strings respectively to 'Bat +', 'Bat N', 'Bat -' and 'PE' terminals of the corresponding I/O terminal block
of the UPS in the parallel system through each battery MCB, as shown in Figure 3-5.
Refer to Figure 3-6 to configure the positive battery string and negative battery string.
Figure 3-6 Internal connection diagram for positive battery string and negative battery string
2. Setting
Power on the system, set each single UPS to shared battery strings configuration through the LCD menu 'Settings' ->
'Shared Battery' from each UPS; set the LCD menu 'Settings' -> 'Battery Cells Number' and 'Single Group Batt Cap'
from each UPS, and each UPS setting must be the same, as shown in Figure 3-7.
UPS 1
Bat+ Bat N Bat- PE
UPS 1 MCB
+ - PE
Positive battery
string
Figure 3-5 Connection diagram of shared battery string in 1 + 1 parallel system
First cell Second cell
＋ ＋
－
Liebert ITA 16kVA And 20kVA UPS User Manual
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Note
UPS 2
Bat+ Bat N Bat-
UPS 2 MCB
+ -
Negative battery string
Third cell
＋
......
－ －
PE
PE
Sixteen cell
＋
Bat +
－
Bat -
PE