Emerson Liebert NX 480V - Manual (Page 80)

Operating Instructions
72
9.2 UPS Startup
The Liebert NX must be fully installed and commissioned before startup, and external power isolators
must be closed. Once those general conditions are met, the UPS may be started.
9.2.1 Startup Procedure
To start the UPS from a fully powered-down condition:
1. Open the UPS door to gain access to the main input circuit breakers.
2. Close CB1, CB2 and CB3 (CB5 is open).
The main input contactor closes automatically and the LCD begins to show start-up
screens. The Rectifier indicator flashes green while the rectifier is starting up. It stops flashing
and becomes solid green about 30 seconds after the rectifier enters the normal operation state.
After initialization, the bypass SCR closes. Because the
output circuit breaker is still open, the UPS channels
power through the Maintenance Bypass Supply line
(CB3). The bypass indicator extinguishes, provided that
the bypass is normal.
The opening display is shown in the figure at right.
The UPS Mimic display indicators will be:
3. Close CB5 (CB1, CB2, CB3 and CB5 are closed).
The Maintenance Bypass supply is now in parallel with the UPS Static Switch supply.
4. Verify that the Bypass indicator is Green, then open CB3.
The UPS powers from static bypass instead of from maintenance bypass. The bypass and load
indicators turn on. The design of the hardware and software ensures uninterrupted output.
5. Close external battery circuit breaker.
After the UPS detects that the battery is connected, the red battery indicator extinguishes
moments after the battery charger starts operation.
The UPS Mimic display indicators will be
!
WARNING
During this procedure the output terminals will become live.
If any load equipment is connected to the UPS output terminals, please check with the load
user and ascertain whether it is safe to apply power to the load. If the load is not ready to
receive power, then ensure that it is safely isolated from the UPS output terminals.
Indicator State
Rectifier indicator Green
Battery indicator Red
Bypass indicator Off
Inverter indicator Off
Output indicator Off
Status indicator Off
Indicator State
Rectifier indicator Green
Battery indicator Off
Bypass indicator Green
Inverter indicator Off
Output indicator Green
Status indicator Amber
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