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Operating Instructions
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9.0 OPERATING INSTRUCTIONS
9.1 Liebert NX Operating Modes
The Liebert NX can operate in any of four modes, as shown in Table 20. This section provides
instructions on switching between modes, resetting the UPS, switching the inverter On and Off and
performing other operations.
Table 20 UPS operating modes
Operating Mode
Circuit Breaker
State Description
Normal
Operation
CB1:ON
CB2:ON
CB3:OFF
CB5:ON
The UPS is powering the load.
On Maintenance
Bypass
CB1:OFF
CB2:OFF
CB3:ON
CB5:OFF
The UPS is shut down but the load is connected to utility power via the
Maintenance Bypass Supply line.
NOTE: The load is not protected against disturbances in AC input power in
this mode.
On Test
CB1:ON
CB2:ON
CB3:ON
CB5:OFF
No load power is supplied by the UPS. The load is connected to utility power
via the Maintenance Bypass Supply line.
NOTE: The load is not protected against disturbances in AC input power in
this mode.
On Static Bypass
CB1:ON or OFF
CB2:ON
CB3:OFF
CB5:ON
The load power is supplied through the static bypass line. This may be
considered as a temporary mode during load transfers between inverter and
maintenance bypass or supply under abnormal operating conditions.
NOTE
1. The user controls and indicators mentioned in these procedures are identified in 8.0 -
Operator Control and Display Panel.
2. The audible alarm may sound at various points during these procedures. It can be canceled
at any time by pressing the SILENCE ON/OFF push button.
NOTE
This section refers to some modes and conditions that are set or adjusted using proprietary
service software. To take advantage of all the available features for the Liebert NX, the unit
must be commissioned by a Liebert factory-trained service engineer.