Liebert NX 1+1 manual Installation, Commissioning a Parallel System

Installation

The basic installation procedure of parallel system is the same as that of single module system. The fol- lowing sections only introduce the installation proce- dures specific to the parallel system.

Cabinet Installation

Parallel system composed of two UPS modules

The two UPS modules that will form the 1+1 system should be placed side-by-side. Each battery cabinet is placed next to its corresponding UPS module.

Preliminary Checks

Each UPS module should have the same rating, the same firmware and the same hardware version. Refer to the instructions in Conditions for Paral- lel System on page 1.

Protective Devices

Refer to the instructions supplied in the Liebert NX installation manual, SL-25215.

Power cables

Wiring of power cables is similar to that of single module system (see the Liebert NX installation man- ual, SL-25215). The bypass sources of all modules should be the same, and the outputs should be con- nected altogether correctly.

NOTE

The length and specifications of power cables including the bypass input cables and UPS output cables should be the same, thus the load can be shared evenly in bypass mode.

Parallel Control Cables

Make the connections described below on the paral- lel logic board (M3) inside the Liebert NX:

•Connect one end of the DB-25 interconnecting cable to the X2_1 connector of UPS 1 and the other end to the X2_2 connector of UPS 2.

•Connect one end of the DB-25 interconnecting cable the X2_2 connector of UPS 1 and the other end to the X2_1 connector of UPS 2.

•Connect one end of the DB-9 interconnecting cable the X1_1 connector of UPS 1 and the other end to the X1_2 connector of UPS 2.

•Connect one end of the DB-9 interconnecting cable the X1_2 connector of UPS 1 and the other end to the X1_1 connector of UPS 2.

The connections are shown above in Figure 2.

Figure 2 Connecting 1+1 system parallel control cables

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#1 UPS Module #2 UPS Module

Parallel Board		Parallel Board
X5
X4		X4
X2-1 X2-2		X2-1	X2-2
	3
X1-1 X1-2		X1-1	X1-2
4
1	2	UPS Unit
	3	Parallel Connection Board
	4	Interconnecting Cables

Commissioning a Parallel System

! CAUTION

The operations in this section must be performed by authorized electricians or qualified technical personnel. If you have any difficulties, contact Liebert Global Services at 800-543-2378.

Check the input and output wiring of each UPS mod- ule. Ensure that the phase rotation sequence of the main inputs and the bypass inputs and outputs of each UPS module are the same. Ensure the parallel cables are connected firmly.

It is assumed that the installation is complete, the system has been commissioned by authorized per- sonnel and the external power isolators are closed.

Before startup, disconnect the load.

Start the UPS modules separately and set the parameters of each UPS module through configura- tion software. Pay particular attention to the param- eters directly relevant to the parallel system:

•UPS Configuration: Each UPS module belonging to the parallel system should be set as Parallel configuration.

•UPS ID No.: Each UPS module should have a unique identification number in the parallel system.

•Parallel system requisite UPS units: Set the mini- mum number of UPS modules to support the user’s expected load. For 1+1 systems this settings needs to be set to 1.

•Parallel system redundant UPS units: Set the redundant number of UPS modules which will not cause the parallel system transfer to bypass even

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