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72 Operation
UPS SYSTEM (Cont’d.)
Overload SCC
MMU
R, S
S
The UPS output current exceeds the rated system load current. This
condition causes an alarm only, the UPS does not shut down.
[Determine cause of the overload. Reduce the load until the overload
condition is corrected. Reset the UPS alarm.]
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
R (MMU)
An alarm message (see lists in SCC and Module Remote Monitor
Indications and Other Alarms That Activate Summary Alarms in
3.1.5 - System Configuration Screens) or the watchdog timer has
activated the Module Summary Alarm.
[Clear alarm conditions, if possible.]
Module N Off Line SCC D
R (MMU)
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.]
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.]
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 3.1.13 - Alarm and Status Messages.
Battery Cycle
Buffer Warning
— D, E 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.
Table 1 Alarm Messages - Meaning and Corrective Action (continued)
Alarm
Message
Cabinet
Location
Special
Functions
Meaning and
Corrective Action in Brackets [ ]
Table 1 Abbreviations
D = auto-dial; L = latches
E = reports 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