LIEBERT NX 1+1 SYSTEM
PRODUCT SPECIFICATION AND INSTALLATION SHEET
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General
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).
! CAUTION
An external maintenance cabinet is strongly recommended to maintain the power supply to load in case of complete maintenance.
Conditions for Parallel System
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)
Features of Parallel System
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
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