Emerson 7400 user manual LS4

Series 7400 Single Phase 1+N UPS

LED	NORMAL	ACTIONS TO BE TAKEN IF ABNORMAL
NUMBER	STATE
LS4	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.
LS5**	OFF	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.
LS6**	ON	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.

**Note that in one-plus-onesystem 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.

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