Liebert UPS System user manual Ups

Chapter 8 Parallel System

Table 8-3 Fault and fault process methods of parallel operation system

No.	Fault description				Reasons					Fault processing
1	Overload	of	parallel	Overload		occurs and			the	Disconnect the load of low priority,
	operation system			redundancy is not available						maintain the power supply to important
										load
				In parallel operation system,
				some UPS unit may require
	Single module UPS			to transfer to bypass due to						If the parallel operation system
2	system	requires to		surge	or	overload,		other		transfers to bypass mode, and the
	transfer	to	bypass	units will transfer to bypass						operation condition enables, all the
				after	receiving		the	signal		UPS units can recover to normal mode
	mode			sent by this UPS unit that						synchronously.
				requires		to	transfer		to
				bypass mode
				The load current of each
3	Load sharing fault			UPS	unit	is	noticeably			Notify the service dept for repairing
				unbalanced, thus the system
				loading ability is affected.
4	Parallel	operation		The board is damaged.						Notify the service dept for repairing
	board fails

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