Emerson 7400 - Manual (Page 64)

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Series 7400 Single Phase 1+N UPS
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 MESSAGE INTERPRETATION
EMERGENCY STOP
INVERTER OFF OR
FAILED
OVERTEMPERATURE
OVERLOAD
BATTERY C/B OPEN
OUTPUT C.B. OPEN
RECTIFIER OFF
OR
FAILED
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 3 and 4 of the UPS auxiliary
terminal block.
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]
Overtemperature is sensed by a normally-closed thermostat
(90º C operating) fitted to each inverter heatsink. If an
overtemperature condition arises, the audible alarm will
accompany this message - the inverter stops and load
transfers to bypass after 3 minutes.
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 as 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.
This is a status indication only. Note that 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.
This is a status alarm. This output isolator must be selected
‘CLOSED’ at all times except when operating on the
maintenance bypass supply.
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.