Emerson 480V Inverter STS Fail, Condition is removed, Error can also leads to the alarm

UPS Status Messages

Table 36 UPS status messages

Event Message	Description / Suggested Action (if any)
Inverter STS Fail	At least one of the static switches of inverter side is open or short circuit. This fault is locked until
	power off. Contact Liebert Global Services for assistance at 800-543-2378 for assistance.
	At least one of the static switches of bypass side is open or short-circuited. This fault is locked
Bypass STS Fail	until power off.
	Contact Liebert Global Services at 800-543-2378 for assistance.
Output Fuse Fail	At least one of the output fuses is open. Contact Liebert Global Services at 800-543-2378 for
	assistance.
Control Power 2 Fail	Control Power 2 is abnormal or lost. Contact Liebert Global Services at 800-543-2378 for
	assistance.
	The UPS is overloaded when the load arises above 105% nominal rating.
	The alarm automatically resets once the overload condition is removed.
	Confirm that the alarm is true by checking the load percent indicated on the LCD panel to
Unit Overload	determine which phase is being overloaded.
	If the alarm is true, measure the actual output current to verify that the indications are valid.
	Disconnect unnecessary load. In a parallel system, a severe load sharing error can also lead to
	the alarm.
	Contact Liebert Global Services at 800-543-2378 for assistance.
	The UPS parallel system is overloaded when the total load arises above 105% nominal rating
	for the set basic number of UPS units. The alarm resets automatically once the overload
	condition is removed.
System Overload	Confirm that the alarm is true by checking the system load percent indicated on the LCD panel
	to determine which phase is being overloaded.
	If the alarm is true, measure the actual output current to verify that the indications are valid.
	Disconnect unnecessary load and ensure the safety. In a parallel system, a severe load sharing
	error can also leads to the alarm.
	The UPS is overloaded and the overload times out.
	Note 1: The highest loaded phase will indicate overload timing-out first.
	Note 2: When the timer is active then alarm “unit overload” should also be active as the load is
	above nominal.
	Note 3: When the timer has expired, the inverter Static Switch is opened and the load
Unit Overload Timeout	transferred to bypass. The inverter shutdown and will restart after 1 seconds.
	Note 4: If the load decreases lower than 95% after 5 minutes, the system will transfer back to
	inverter mode.
	Confirm that the alarm is genuine by checking the load percent indicated on the LCD. If an
	overload is indicated then check the load, and investigate any additional load connected prior to
	the alarm (if applicable).
Inverter Overcurrent	The current of inverter IGBT is over limit. If the fault will not reset, contact Liebert Global
	Services at 800-543-2378 for assistance.
	The phase sequence direction of bypass voltage is reversed.
	Normally, the phase of Phase B lags 120 degrees behind Phase A, and the phase of Phase C
Bypass Phase Reversed	lags 120 degrees behind Phase B.
	Verify that the phase rotation of the bypass supply presented to the UPS is correct, and rectify it
	if it is found to be in error. Contact Liebert Global Services at 800-543-2378 for assistance.
Load Impact Transfer	A transfer to bypass occurred due to a large step load. The UPS should recover automatically.
	Turn on connected equipment in sequential order to reduce the step loading of the inverter.
	The load is on bypass power due to excessive number of transfers that occurred within the last
Transfer Timeout	hour.
	The UPS will recover automatically and will transfer the load back to inverter power within an
	hour.
Load Sharing Fault	UPS units working within a parallel system are not sharing load current correctly. Contact
	Liebert Global Services at 800-543-2378 for assistance.
DC Bus Abnormal	Shut off inverter due to abnormal DC bus voltage.
	Contact Liebert Global Services at 800-543-2378 for assistance.
System Transfer	The whole paralleled UPS system transferred to bypass at the same time. This message will
	appear on the UPS which passive transfer to bypass.
Parallel Board Fault	Parallel board is not working correctly. Contact Liebert Global Services at 800-543-2378 for
	assistance.

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