7400 Series UPS User Manual Chapter 6 - Troubleshooting
Single Module and One plus One Systems Troubleshooting UPS System
6310018a.02.doc
6-5
Issue 2
(02/98)
6.2 Display panel message interpretation
The following table lists the various messages displayed on the operator
panel together with a description of their interpretation.
DISPLAY
MESSAGES
INTERPRETATION
EMERGENCY STOP
ALARM
This alarm indicates that the UPS was shut down by means of the local or remote (if
fitted) emergency stop pushbutton which of course is normally due to operator action
- investigate why the emergency stop pushbutton was pressed.
If the emergency stop pushbutton was not pressed then check the continuity of the
remote emergency stop line (if fitted), and if no remote emergency stop line is fitted
then check that a link is connected between terminals 4 and 5 of the UPS auxiliary
terminal block.
INVERTER OFF OR
FAILED ALARM
This alarm is active whenever the inverter is not producing its correct output voltage;
either because it has been switched OFF or due to an internal fault.
The alarm will accompany other alarms such as [OVERLOAD], [LOAD ON
BYPASS]
OVER TEMPERATURE
ALARM
Over temperature is sensed by a normally-close thermostat (90°C operating) fitted to
each inverter heat sink. If an over temperature condition arises, the audible alarm
will accompany this message - the inverter stops and load transfers to bypass after 3
minutes.
OVERLOAD
ALARM
The inverter overload has an inverse load/time characteristic - i.e. it will accept
125% overload for 10 minutes and 150% for 60 seconds. If this characteristic is
exceeded then the load transfers to the bypass supply, the inverter stops and the
overload alarm annunciates. The [OVERLOAD] alarm will annunciate at soon as the
load exceeds 100% of the UPS rating, and the load will transfer to bypass some time
later -depending on the degree of overload present.
BATTERY CB OPEN or
BATTERY FUSE FAIL
ALARM
This is a status indication only. Note that if the UPS if operating with the battery
circuit breaker open and the mains power fails then the UPS output will also fail
together with load power. Also check battery fuses.
OUTPUT CIRCUIT
BREAKER OPEN ALARM
This is a status alarm. The output isolator must be selected ‘CLOSED’at all times
except when operating on the maintenance bypass supply.
RECTIFIER OFF OR
FAILED ALARM
This alarm is active whenever the battery charger (rectifier) is not producing its
correct output voltage; due to either an input supply failure, an internal fault, or an
open input circuit breaker.
UPS ON
MAINTENANCE BYPASS
WARNING
This is a status warning that the load is being powered through the maintenance
bypass line and is unprotected from mains supply abbreviations. Due to the fact that
the UPS power supplies are fed by the input circuit breaker, this message will
disappear if the input isolator is opened (and bypass isolator opened on a split bypass
system) while the load is on the maintenance supply.
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