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
