User Manual 10H52188UM51 - Rev. 1 - 09/2011 45
Liebert NXC Operation and Display Panel
Alarm message Description
Bypass phase reverse
The phase sequence direction of the bypass voltage is reversed. Normally, the phase of phase B lags 120
degrees behind phase A, and the phase of phase C 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 the fault is
found
Load impact transfers
bypass
A transfer to bypass occurred due to a large step load. The UPS will recover automatically. Turn on the load
in sequential order for reducing the step load of the inverter
Transfer time-out
The load is on bypass power due to the excessive number of transfers that occurred within the last hour. The
UPS will recover automatically and will transfer the load to inverter power within an hour
Bus abnormal DC bus voltage is abnormal. Inverter shuts down. Load transfers to bypass
DC bus over voltage
Rectifier and inverter are off because the DC bus voltage is too high. Check whether there is a fault in
rectifier side. If not, check whether there is an overload. After recovering the fault, restart the inverter
Bypass over current Bypass current is over limit above 135% rating. The UPS just alarms without any action
Setting save error Historical records are not saved (Reserved)
Input Disconnect Fault AC mains input neutral line is not checked out
Protocol version clash Firmware incompatibility between monitor board and Digital Signal Processor (DSP) board
Manual on Manually turn on the inverter through pressing ON on the operation and display panel
Manual off Manually turn off the inverter through pressing OFF on the operation and display panel
EPO Press the EPO button directly or receive the external EPO command
Transfer confirm Prompt to press the Enter button to acknowledge that an interrupted load transfer to bypass will happen
Transfer cancel Prompt to press the ESC button to avoid that an interrupted load transfer to bypass will happen
Fault clear Press FAULT CLEAR
Alarm silence Press ALARM CLEAR
Turn on fail
Inverter failed to turn on manually. The reason may be the invalid operation (maintenance bypass air
breaker closed), or DC bus or rectifier not ready
Alarm silence cancle Press FAULT CLEAR or ALARM CLEAR
Bypass mode The UPS is in Bypass mode
Normal mode The UPS is in Normal mode
Battery mode The UPS is in Battery mode
Check UPS output
1. Whether the EPO terminal is on the dry contact port 4
2. Whether the LCD displays “Parallel comm. Fail”
Battery float charging Battery status (floating charge mode)
Battery boost charging Battery status (boost charge mode)
Battery discharging Battery status (discharge mode)
Battery period testing Automatically periodic battery maintenance test (20% capacity discharge)
Batt. capacity testing User initiated battery capacity test (100% capacity discharge)
Batt. maint. testing User initiated maintenance test (20% capacity discharge)
UPS system testing User initiated UPS system self-test
Inverter in setting Inverter is starting up and synchronizing
Rectifier in setting Rectifier is starting up and synchronizing
Battery reverse Reconnect the battery, and check the battery wiring
No battery Check the battery and battery wiring
Auto start
UPS is off when the battery discharges completely, the inverter will automatically start after the mains is
restored
REC FLASH UPDATE Ongoing update of rectifier firmware
INV FLASH UPDATE Ongoing update of inverter firmware
MONITOR FLASH
UPDATE
Ongoing update of monitor firmware
DSP softwar error Inverter software does not match the rectifier software
Operation invalid and
Bypass unable to trace
Alarm combination, when the two alarms appear at the same time, the UPS I/O cable connection mode is
not suitable with the setting mode (3-in 3-out or 3-in 1-out)
Note:
If the alarm is caused through setting the software value by Emerson authorized engineer, and when you wish to change the setting
values, please get in touch with the Emerson local customer service centre
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