Emerson 480V ユーザーズマニュアル

The basic installation procedure of parallel system is the same as that of single module system. The 

following sections introduce only the installation procedures specific to the parallel system.

• Each UPS module must have the same bypass source.
• The outputs of all UPS modules are connected altogether.
• The main inputs can be from different sources, but the phase rotation sequence of main inputs, 

bypass inputs and outputs must be correct and the same.

• The parallel logic cable and load sharing cable must be connected in a ring correctly (see 

Parallel system composed of two or more UPS modules using parallel cabinet
The UPS modules that will form the parallel system should be placed side-by-side. Each battery cabi-

net is placed next to its corresponding UPS module.
The parallel cabinet should be placed in the middle of the system.

Each UPS module should have the same firmware and the same hardware version. Refer to the 

instructions in 4.3.1 - Conditions for Parallel System.

Wiring of power cables is similar to that of a single module system (See 2.1 - Power Cabling). The 

bypass sources of all modules should be the same, and the outputs should be connected altogether cor-

rectly.
Power cables are field-supplied. Power cables to the UPS’s of the paralleling cabinet must be routed 

through either the top or bottom entry access of the UPS.

Make the connections listed below on the parallel logic board (M3) inside the Liebert NX. (See 

Figure 23 for the location of the parallel logic board):
Shielded and double-insulated control cables, available in lengths of up to 100 feet (30m), must be 

interconnected in a ring configuration between UPS modules as shown below. The ring configuration 

ensures high reliability of the control (refer to Figure 18).

NOTE
When paralleling UPS's with different power ratings, the power rating of the largest UPS can 

NOTE
The system input and/or output circuit breaker is to be field-supplied. See Table 8 for current 

NOTE
The length and specifications of power cables including the bypass input cables and UPS