Emerson 480V, 60HZ user manual 4.2Configuring Parallel System Operation, 4.2.1General

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Figure 14 Load Bus Synchronization cable connection with multi-module systems

	UPS
Parallel Board		Parallel Board
X3	P5	X3	P5
	X4		X4
X2-2 X2-1		X2-2 X2-1
P2	P1	P2	P1
X1-1 X1-2		X1-1 X1-2
P3	P4	P3	P4
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	Parallel System I		A

		UPS
	Parallel Board		Parallel Board
	X3	P5	X3	P5
		X4		X4
LBS Cable	X2-2 X2-1		X2-2 X2-1
	P2	P1	P2	P1
	X1-1 X1-2		X1-1 X1-2
	P3	P4	P3	P4
	8
		Parallel System II		B

The LBS function is activated with configuration software; when the LBS takes effect, the graphic LCD will display “LBS active.”

4.2Configuring Parallel System Operation

4.2.1General

The Liebert NX uses intelligent and reliable decentralized technology to achieve parallel operation of two or more modules.

The parallel 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 repairs without affecting the ordinary operating conditions of the system (depending on the redundancy level).

4.2.2Features of Parallel System

•The controls for parallel UPS module operation are standard in the Liebert NX, and the configu- ration can be set up by changing the settings in configuration software.

•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, shut- ting 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.

•The total load of the parallel system can be queried from each module’s liquid crystal display screen.

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