Emerson 7400 - Manual (Page 63)

54
Series 7400 Single Phase 1+N UPS
** Note that in one-plus-one system configured with a redundant
module, it is possible for one of the two modules to shut down (due
to fault for example) without turning on its static switch. In fact
when in a redundant module configuration a module’s static switch
is disabled whenever its partnering module is on line. Therefore in
the event of a fault you are likely to see LS4, LS5 & LS6 all OFF.
LED NORMAL ACTIONS TO BE TAKEN IF ABNORMAL
NUMBER STATE
LS4
LS5**
LS6**
ON
OFF
ON
If this led is OFF it signifies that the inverter is not
producing its correct output voltage.
Check the following:
a) If [OVERTEMPERATURE] OR [OVERLOAD] alarm
messages are active then (after allowing the
UPS to cool / checking that the load current on
the bypass line is not excessive) press the reset
switch on the UPS Logic Board.
b) Press the Inverter ON pushbutton
c) If the dc busbar is below 320V (330V for 80-125
kVA) then do checks as per LS1 above
d) Check that slide switch I3 is closed on the UPS
Logic Board is closed.
e) If the inverter works OK when mains is available
but not when mains is unavailable then check
the dc power supply fuses.
If the above checks prove unsatisfactory then seek
qualified assistance.
If this led is ON then it signifies that the load has been
transferred to the static bypass supply and the output
circuit breaker is closed. This indication should be
mutually exclusive with LS6 described below - check
out LS6 actions.
If LS4 is also OFF then refer to LS4 checks.
If LS6 is OFF but LS4 is ON then check the following:
a) Ensure that the output isolator is closed then
press the Reset button on the UPS Logic Board.
b) Ensure that slide switch l3 on the Static Switch
Logic Board is in the AUTO position.
If the above checks prove unsatisfactory then seek
qualified assistance.