Emerson 7400 - Manual (Page 62)

53
Series 7400 Single Phase 1+N UPS
LED NORMAL ACTIONS TO BE TAKEN IF ABNORMAL
NUMBER STATE
LS1
LS2
LS3
ON
ON
ON
If this led is OFF it signifies a problem either with the
incoming mains supply or the rectifier section. See
accompanying alarm messages.
Check the following:
a) Input isolator is closed.
b) Input supply voltage is within 20% of nominal
c) Input fuses are O.K.
d) Power supply fuses are OK
(Note: LS1 and LS2 on
the AC Power Supply Board will be OFF if either of these
fuses are ruptured).
e) Mains sensing fuses on the High Voltage
Interface board F4, F5, F6 are OK.
f) Check that slide switch I2 on the UPS Logic
Board is closed.
If the above checks prove satisfactory then seek
qualified assistance.
If this led is OFF it signifies that either the battery circuit
breaker is open or that the dc busbar voltage is below
320V dc. (For 80kVA to 125kVA models, this voltage is
330V dc ).
The battery circuit breaker will open automatically if the
dc voltage falls below this level.
Check the following:
a) Battery circuit breaker is closed.
b) DC busbar voltage – if not above 320V then
carry out checks as per LS1 (mains failure)
above. If the dc busbar voltage is greater than
320V ( and 330V dc for 80-125kVA models); If
you are unable to close the battery circuit
breaker, then seek qualified assistance.
c) If the battery circuit breaker trips as soon as
mains power is disconnected then check the dc
power supply fuses.
If this led is OFF it signifies either that the bypass supply
is not within acceptable tolerances or that the bypass
supply isolator is open.
Check that the bypass supply isolator is closed, the
supply is available and within specifications.