Liebert NX UPS System user manual UPS is confirmed to overload and the overload times out

Operator Control Panel and Display

Table 22	UPS messages (continued)
Message		Description / Suggested Action (if any)
		The UPS is confirmed to overload 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 Over load Timeout		transferred to bypass. The inverter shutdown and will restart after 10 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).
Byp. Abnormal Shutdown		Both bypass and inverter voltages unavailable. Load interruption
Inverter Over Current		Inverter Pulse Width Modulation module overloaded.
		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
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 Time-out		hour.
		The UPS will recover automatically and will transfer the load back to inverter power within an
		hour.
Load Sharing Fault		UPS modules within a parallel system are not sharing the load current equally.
DC Bus Abnormal		DC input voltage to inverter beyond limits. Inverter shuts down. Load transfers to bypass.
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		Malfunction of the paralleling control circuits of this UPS module. Can cause “System Transfer”
		to bypass.
		Rectifier, inverter and battery converter were shutdown because DC bus voltage is too high.
DC Bus Over Voltage		Check whether there is a fault in rectifier side. If no, then check whether overload occurs.
		Restart the inverter after resetting the fault
		The parallel cables are not connected correctly in a parallel system.
Parallel Connect Fault		Reset the fault by pressing the “fault clear” button, then restart the inverter by pressing the
		“inverter on” button.
Bypass Over Current		Bypass current is over limit above 135% rating. The UPS just alarms and does nothing.
LBS Active		Load Bus Synchronisation is active. The UPS is acting as an LBS master or slave in a dual bus
		configuration.
Setting Save Error		History records not saved. (Reserved)
Mains Neutral Lost		AC Input mains reference neutral not detected.
Protocol version clash		Firmware incompatibility between Monitor Board and Digital Signal Processor Board.
Battery ground fault		Battery leakage to ground detected (option)
Inv. Turned On Manually		Manual Turn On via front panel
Inv. Turned Off Manually		Manual Turn Off via front panel
EPO		Emergency Power Off direct access key pressed or external command received
Transfer Confirm		Prompt to press “enter” key to acknowledge that an interrupted load transfer to bypass will
		happen.
Transfer Cancel		Prompt to press “ESC” key to avoid that an interrupted load transfer to bypass will happen.
Unit Off Confirm		Prompt to press “enter” key to acknowledge that the UPS will be disconnected from other
		paralleled UPS modules.
System Off Confirm		Prompt to press “enter” key to acknowledge that the all paralleled UPS will be disconnected
		from the load.

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