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UPS SYSTEM (Cont’d.)
Overload
Transfer
SCC D, F, L, S
The load on the UPS has exceeded the current versus time window of
system overload capacity. The UPS system transfers the load to bypass.
Reduce the load. If the system does not initiate an automatic load
retransfer, manually retransfer the critical load from the bypass line to the
UPS. Reset the alarm.
Module Summary
Alarm
SCC S An alarm message (see lists in SCC and module remote monitor
indications and Other alarms that activate summary alarms in 3.2.6 -
System Configuration Screens) or the watchdog timer has activated the
Module Summary Alarm.
Clear alarm conditions, if possible.
MMU R
Module N Off
Line
SCC D The output circuit breaker of Module N is open. The number N will identify
the module (1 through 6).
Review active alarms at Module N and clear alarm conditions, if possible.
MMU R
Inverter
Nonsynchronized
MMU —
Inverter output is not synchronized with the UPS system critical bus. This
also means the output circuit breaker is open and should not be closed
until the output is in sync. This condition may correct itself. If not, shut
down the UPS module and then perform a start-up procedure.
Contact Liebert Global Services if condition persists.
Overload
Shutdown
MMU D, F, L, S
The UPS output current has exceeded 175% of the rated full load or the
overload capacity has been exceeded. The UPS module is taken off-line
and shut down.
Contact Liebert Global Services at once. Do not attempt to reset circuit
breakers.
Reverse Power MMU D, F, L, S
Excessive reverse power flow from the critical bus into the UPS inverter
has occurred, probably because of low inverter output voltage or a phase
mismatch. The UPS module is taken off-line and is shut down.
Contact Liebert Global Services immediately. Do not attempt to reset
circuit breakers.
Rectifier Fuse
Blown
MMU D, F, S
At least one of the fuses has opened or a rectifier fault was detected. UPS
module is taken off-line and is shut down.
Contact Liebert Global Services immediately. Do not attempt to reset
circuit breakers.
Inverter Fault MMU D, F, S
At least one of the fuses has opened or an inverter fault was detected.
The UPS module is taken off-line and is shut down.
Contact Liebert Global Services immediately. Do not attempt to reset the
circuit breakers.
Communication
Failure
SCC S
The COM FAIL status message is as important as an alarm message.
Refer to 3.2.14 - Alarm and Status Messages.
Battery Cycle
Buffer Warning
MMU D, S
The optional Battery Cycle Monitor can retain information about the last
132 battery discharge events. When the storage buffer approaches its
capacity, this warning message is broadcast via terminal and modem
communication channels and a complete listing of all records is sent to
the terminal port. The message clears after 30 seconds.
Battery Exercise MMU —
Battery self-test can be enabled from System Options screen. For test to
start, the following conditions must be valid:
1. No Battery Overtemp Alarm must exist.
2. Battery input and output circuit breakers must be closed.
3. All three input volt phases must be within nominal range (+10%, -20%).
4. DC volts must be greater than (DC Ref) -20V. For a 540 bus, the
nominal float voltage for 240 cells (the DC voltage reference setting) the
DC voltage on the battery must be greater than 520VDC.
5. Battery charge must be greater than 90%.
6. Load must be greater than 15%.
Table 9 Alarm messages - meaning and corrective action (continued)
Alarm
Message
Cabinet
Location
Special
Functions Meaning and Corrective Action
Table 9 Abbreviations
D = auto-dial; L = latches
E = logs only; R = remote
F = freezes; S = summary
D* = auto-dial initiated by Auto Transfer to Bypass if load is on UPS when alarm occurs
D# = auto-dial initiated through Module N (1-6) off-line