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Operation
52
BYPASS, continued
Static Switch
Unable
D, S
The UPS output is not synchronized to the bypass power source, the static bypass switch is
disconnected, or it has failed internally. Emergency and overload transfer to the bypass
source is not available. If the module has a manual Static Switch Disconnect, set it to ON
(closed). If the module does not have a manual disconnect switch, open and re-close the
static switch fuseholder. If the alarm conditions are automatically corrected, reset the alarm
to clear it. Contact Liebert Global Services if the alarm stays on.
Bypass Not
Available
The bypass power source voltage is not within specifications. Correct the bypass AC power
source.
Bypass Phase
Sequence
Wrong
D, L, S
The power conductors on the bypass line are not wired to the UPS in the required
sequence. This alarm should appear only during initial start-up or after a repair to the source
power system. Disconnect power from the bypass line and correct the wiring. Liebert Global
Services must be present during initial start-up of your UPS System.
UPS SYSTEM
Input Current
Unbalanced
D, E
At least one input phase differs from the average current by 10% or more for four (4) hours.
Contact Liebert Global Services. If the condition persists, transfer the load to the bypass
line.
Control Power
Fail
D, L, S
The logic control power supply from the UPS output is not operating properly. The UPS
module continues operating but will shut down if the input power fails. Contact Liebert
Global Services immediately.
Output Over/
Underfre-
quency
D, L, S
Output frequency differs from the nominal (60 Hz) by more than 0.5 Hz. No transfer or
shutdown occurs. Contact Liebert Global Services at once.
Output
Undervoltage
D, F, L, S
The UPS module output voltage is under the minimum permitted (-12%) deviation from
nominal. The load automatically transfers to the bypass line. If the alarm condition is no
longer present, reset the alarm and retransfer the load from bypass to UPS. Contact Liebert
Global Services if alarm persists.
Output
Overvoltage
D, F, L, S
The UPS module output voltage is above the maximum permitted (+10%) deviation from
nominal. The load automatically transfers to the bypass line. The UPS module is shut down
and isolated. Contact Liebert Global Services at once. Do not attempt to reset circuit
breakers.
Overload D, R, 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
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.
Reverse
Power
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
shut down and isolated. Contact Liebert Global Services immediately. Do not attempt to
reset circuit breakers.
Rectifier Fuse
Blown
D, F, S
At least one of these fuses has opened. The UPS automatically transfers the critical load to
the bypass line. Circuit breakers trip open to shut down and isolate the UPS module.
Contact Liebert Global Services immediately. Do not attempt to reset the circuit breakers.
Inverter Fault D, F, S
Hardware
Shutdown
D*
At least one of the following alarm conditions is present: Inverter Fault, Rectifier Fuse Blown,
Reverse Power, Overload Shutdown, logic power supply failure or inverter output symmetry
failure. The load automatically transfers to the bypass line. The UPS module is shut down
and isolated. Contact Liebert Global Services at once. Do not attempt to reset the circuit
breakers.
Table 4 Alarm messages and corrective actions, continued
Alarm
Message
Special
Functions Meaning and Corrective Action
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