Liebert Series 600T manual One Module Off-Line Load on UPS

3.2.5One Module Off-Line

A multi-module UPS system can be supplied with a back-up (redundant) UPS module, which is the typical con- figuration. 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 sys- tem if any one of the modules is disconnected (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 Sys- tem 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 dis- played 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 52 One Module Off-Line (Load on UPS)

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

Output MIB

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

Operation 83

DISCONTINUED

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