Emerson 7400 Series User Manual page 27

Series 7400 Single Phase 1+N UPS
How to turn OFF the System but continue to provide
This procedure should be followed if one-plus-one is to be powered-down while
continuing to supply load through the maintenance bypass line. Note that during this
procedure the load will be unprotected against mains supply disturbances once the
inverter(s) has been switched off.
Step Action
1. Ensure that LS3 is illuminated on the
mimic panels (indicating that the
static bypass supply is healthy).
2. Press the Inverter OFF switch (S6) on
both modules
3. Close the
Isolator on both modules.
Open the Output Isolator on both
4.
modules.
5. On each module - Open the battery
circuit breaker followed by the input
Isolator (and Static Bypass Isolator if
separate.
bypass
auxiliary cubicles).
6. Isolate the UPS input supply from the
mains distribution panel to make the
UPS safe for work to be carried out
internally.
The following points will be live within the UPS:
- Bypass supply input terminals
- Maintenance Bypass Isolator switch
- Static Bypass Isolator Switch (if fitted)
- UPS output terminals
Load power through the Maintenance Bypass
Maintenance Bypass
For 110V systems Static
isolator is mounted
Response
Mimic panel LEDs LS4 and LS6 should
extinguish on both modules and LS5
should illuminate to show that the load
has been transferred to the static
bypass line.
Note: On a redundant system both Inverter
OFF switches (S6) must be operated before
LS5 illuminates but in a non-redundant system
the Inverter OFF switch must be pressed on
one module only before LS5 illuminates.
However, as the load is transferred to the
static bypass, the second module should be
turned OFF also.
Mimic panel LEDs - No change
Mimic panel
extinguish on both modules.
All the operator panel led indications
and messages should extinguish as
the mains
supplies decay.
in
WARNING
LED LS5 should
driven internal power
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