Liebert 1000kVA manual One Module Off-Line, One module off-line, load on UPS

Operation

3.3.5One Module Off-Line

A multi-module UPS system can be supplied with a back-up (redundant) UPS module, which is the typical configuration. A redundant system includes one more module than the number required to supply the critical load. A redundant system operates in the redundant mode if all modules are ON LINE. Note that the UPS system can also operate in the redundant mode with one module OFF LINE if the critical load is reduced so that not all ON LINE modules are required. The UPS modules share the load and the critical load will remain on the UPS system if any one of the modules is discon- nected (goes OFF LINE) for maintenance or because of an internal fault.

The system control logic monitors the connected critical load and the number of UPS modules ON LINE. If the UPS system is operating in the redundant mode, the REDUNDANT status message will be displayed at the System Control Cabinet (SCC). If the UPS system is operating in the non- redundant mode (redundant module is OFF LINE or was not included in the system configuration), the NON-REDUNDANTstatus message is displayed at the SCC. In the Non-Redundant mode, the critical load will be transferred to bypass if any UPS module goes OFF LINE and you must transfer the load to bypass in order to perform maintenance on any UPS module.

Figure 57 One module off-line, load on UPS

		RIB			RIB			RIB		BFB
UPS #3			UPS #2			UPS		#1
						CB1
CB1			CB1
								SBS
										BIB
	R			R			R		SBB
	I			I			I				MBB
CB2			CB2			CB2		System		SKRU
								Controls

Output

MIB

					SCCT
	MBD				To Critical Load
			MBD		MBD
					SCCT
Battery
		Battery		Battery
					(can accommodate up to 6 UPS modules)

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