Connecting Parallel Cables - Emerson Liebert ITA User Manual

Input cable
Configure each UPS with extenal input MCB and extenal output MCB when carring out the power distribution for the parallel
system, as shown in Figure 3-2.
Changing power distribution mode
This product is compatible with 3-in 3-out/3-in 1-out, factory default: 3-in 3-out.
If you need to change the mode from 3-in 3-out to 3-in 1-out or from 3-in 1-out to 3-in 3-out, carry out the parallel
connection after changing the single system to the needed system (Refer to Changing power distribution mode in
2.5.1 Connecting I/O cables for the changing method).

3.4.2 Connecting Parallel Cables

The parallel system provides parallel cable option. The parallel cables form a ring connection through the parallel
ports on the rear panel of the UPS. The cable connection schematic diagram of 3 + 1 parallel system is shown in
Figure 3-3. The first port on the left is DB9 male port (pin shape), and the second port on the left is DB9 female port
(hole shape).
Chapter 3 Parallel UPS Installation And Commissioning
User input power
distribution unit
Figure 3-2 Block diagram of three UPSs parallel system
Liebert ITA 16kVA And 20kVA UPS User Manual
®
User output power
distribution unit
UPS1
UPS2
UPS3
Warning
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Output cable