Liebert UPS System user manual Ups

Chapter 7 Troubleshooting

No.1	Fault description	Reason		Actions to be taken
		The system transfers to bypass
49	Transfer to bypass	mode due to surge current and back		Avoid applying load abruptly and the UPS
	due to surge	to inverter mode after load is		can recover automatically
		decreased
	User’s wrong	Wrong operation such as start the
50		UPS with the maintenance bypass		Operate with reference to User’s Manual
	operation
		switched on
	The actual transfer	Transfer times exceed the times set
51	times exceed the	by background. The system will stay		Avoid frequent overload
	permissible transfer	in bypass mode until next hour.
	times per hour
		Table 7-2 Fault of parallel	operation system

No.	Fault description				Reasons			Fault processing
1	Overload	of	parallel	Overload	occurs and		the	Disconnect the load of low priority, maintain the
	operation system			redundancy is not available				power supply to important load
				In parallel operation system,
				some UPS		module	may
	Neighbouring		UPS	require to transfer to bypass				If the parallel operation system transfers to
2	module	requires to		due to surge or overload,				bypass mode, and the operation condition
	transfer	to	bypass	other modules will transfer to				enables, all the UPS modules can recover to
	mode			bypass	after	receiving	the	normal mode synchronously.
				signal sent by this UPS
				module	that	requires	to
				transfer to bypass mode
				The load current of each UPS
3	Load sharing fault			module 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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