70 Operation
Table1 Alarm Messages - Meaning and Corrective Action
Alarm
Message
Cabinet
Location
Special
Functions
Meaning and
Corrective Action in Brackets [ ]
AC INPUT
InputFail MMU — Therectifier input line voltage is outside of specified limits or the
inputcircuit breaker is opened while the battery circuit breaker
remainsclosed. The battery supplies power to the critical load
throughthe UPS inverter.
DC BUS
DCGround Fault MMU L,S Eitherthe positive(+) or negative (-) DC bus is grounded. No transfer
orshutdown occurs.
[ContactLiebert Global Services at once. Do not attempt to locateor
repairthe fault.]
DCCapacitor
FuseBlown
MMU D,F, S At least one DC capacitor fuse has opened.The UPS moduleis
takenoff-line and the input and battery circuit breakers trip open.
[ContactLiebert Global Services at once. Do not attemptto reset the
circuitbreakers.]
BatteryCB Open MMU R,S Them odulebattery circuit breaker (MBD) is open. This circuit
breakercan be opened either manually or automatically in a UPS
shutdownprocedure. If the UPS is operating with this breaker open,
thecritical load is not protected from loss of the utility source
power.
[AfterAC power is restored and the DC bus is at 100% operating
voltage,manually close the batterycircuit breaker so the rectifier can
chargethe battery.]
Battery
Discharging
MMU R, S Thebattery is discharging. Thisoccurs whenever the battery
suppliespower to the load for more than 5 seconds because of input
powerfailure, a rectifier problem, or an overload condition.If the
inputpower or a source of auxiliary power is restored to the UPS
module,the UPS automatically returns to normal operation.
[Watchthe battery voltage carefully. Reduce the load (begin
controlledshutdown) to extend the battery back-up time. Reset the
UPS alarmsafter the input power is restored. The message clears
after30 seconds.]
LowBattery
Warning
MMU R, S Thebattery voltage is approachingt he minimumdischarge voltage
(approximately5 minutes remaining).
[Completethe controlled shutdown of the critical load. Reset the
alarmsif the inputpower is restored before shutdown.]
LowBattery
Shutdown
MMU D,F, L, S Thebattery voltage has decreased to the minimum discharge value.
TheUPS moduleis taken off-line (no power to the critical load)
andthe battery and input circuit breakers trip open.
[Performa UPS system start-up procedure when AC power
becomesavailable.]
DCOver-Voltage
Shutdown
MMU D,F, L, S Themaximum preset value of the DC Bus voltage has been
exceeded.The UPS module is taken off-line and the input and
batterycircuit breakers trip open.
[ContactLiebert Global Services at once. A faultmay have occurred
withinthe UPS. Do not attempt to reset the circuit breaker.]
BYPASS
LoadOn Bypass SCC D, E,F The critical load is being suppliedpower from the bypass line, and is
thereforeexposed to utility power disturbances.
[Clearall of the alarms before attempting to retransfer the load from
thebypass line to the UPS.]
Table 1 Abbreviations
D= auto-dial; L= latches
E= reports only ; R= remote
F= freezes; S = summary
D*= auto-dial initiatedby Auto Transfert oBypass if load is on UPS whenalarm occurs
D#= auto-dial initiatedthrough Module N( 1-6)off-line
DISCONTINUED
PROD U C T