Liebert EMERSON NX 1+1 User Manual

The Liebert NX UPS uses intelligent and reliable 

decentralized technology to achieve parallel opera-

tion of two modules of the same rating.
The 1+1 system is used to:
• Increase the reliability of the system to ensure 

adequate power supply to the critical load con-

nected.

• Increase serviceability and allow the execution of 

maintenance operations and reparations without 

affecting the ordinary operating conditions of the 

system (depending on the redundancy level).

1. Each UPS module should have the same rating, 

the same firmware and hardware version.

2. Each UPS module must have the same bypass 

source.

3. The outputs of all UPS modules are connected 

altogether.

4. 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.

5. The parallel logic cable and load sharing cable 

must be connected in a ring correctly (See 

Figure 2)

1. The hardware and firmware for parallel UPS 

module operation is standard in the Liebert NX, 

and the configuration can be set up by changing 

the settings in configuration software.

2. It is easy to install the parallel cables in a ring, 

providing high reliability and redundancy. And 

the intelligent paralleling logic provides the user 

with maximum flexibility. For example, shutting 

down or starting up the UPS modules in the 

parallel system can be done in any sequence. If an 

overload transfer occurs, the whole system can 

recover automatically from bypass mode after the 

overload is cleared.

3. The total load of the parallel system can be 

queried from each module’s liquid crystal display 

screen.

4. Optional monitoring background software can 

treat the entire parallel system as a big 

single-module UPS, and provide corresponding 

management. It can also get the information for all 

modules by connecting to just one of the modules.