5.7 Alarm List
Table 5.4 below provides the complete list of UPS alarm messages that display either on the Event menu or on the Records
menu.
Alarm Explanation
Input Phase Reversed The AC input phase rotation is reversed.
Input Voltage Abnormal The mains voltage is outside specifications and results in rectifier shutdown.
Input Freq. Abnormal The mains frequency is outside specifications and results in rectifier shutdown.
Input Undervoltage At least one phase main input voltage is within 132 V to 176 V, thus the load should be derated.
Input Fuse Fail The main circuit input fuse of the module is disconnected.
Input Backfeed Battery voltage fed back to rectifier input.
Input Current Abnormal Battery load sharing imbalance or rectifier input current abnormal.
Input Current Limit Input current over limit.
Input Neutral Missing AC rectifier input neutral line not detected.
Rectifier Fault Rectifier failure (bus voltage is too high or too low, or battery discharge SCR short circuit).
Rec. Soft Start Fail Owing to low DC bus voltage, the rectifier will report this alarm.
Rectifier in Setting The rectifier starts up and is in synchronization.
Inverter Fault The inverter starts up and is in synchronization.
DC Bus Abnormal Shutdown The DC bus voltage is abnormal and results in inverter shutdown. The load transfers to bypass.
DC Bus Overvoltage
The rectifier, inverter and battery converter shutdown because the DC bus voltage is too high. The load
transfers to bypass.
Load Impact Transfer
A transfer to bypass occurred due to a large step load. The UPS can recover automatically. Turn on the load
equipment in stages to reduce the load impact on the inverter.
Excess Auto Rexfers The load remains on bypass power owing to excessive number of transfers that occurred within the one hour.
Excess ECO Auto Xfers The load remains on bypass power owing to excessive number of transfers that occurred within the one hour.
Other Module Xfer
All UPSs in the parallel system transfer to bypass at the same time when one of them needs to transfer to
bypass. This message appears on the touchscreen of the UPS with passive transfer to bypass.
Load Sharing Abnormal The UPSs in a parallel system are not sharing the load current correctly.
Byp. Abnormal Shutdown Both the bypass and inverter voltages are abnormal, and the output is off.
Inverter in Setting The inverter parameters of this machine are being monitored and synchronized.
Inverter Asynchronous
The output voltage and bypass voltage are misaligned in phase. This alarm resets automatically once the
condition is no longer true.
Inverter Relay Fail At least one of the inverter relays is opened or shorted. This fault is locked until mains power off.
Overvoltage N-GND The neutral ground voltage is too high. Check whether the output wiring is shorted to the chassis.
Bypass Abnormal
The amplitude or frequency of the bypass voltage exceeds the limit. This alarm automatically resets once the
bypass voltage returns to normal.
Table 5.4 Alarm List
5 Operator Control and Display
Panel
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Vertiv™ Liebert® APM2 30 to 120 kVA Modular UPS User Manual
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