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2.5 Shutdown Procedures
2.5.1 Module Shutdown Procedure
Perform a Module Shutdown Procedure when you want to remove power from a UPS module.
Read all warnings in 3.0 - Maintenance before performing any maintenance on your Liebert NXL
UPS. These warnings and cautions must be observed during any work on the UPS.
Use the module Monitor/Mimic Display to determine the operating condition of the UPS module.
UPS Shutdown Procedure
1. Press the “Shutdown” menu button on the touchscreen.
The Shutdown screen will appear in the multipurpose window (see Figure 15).
2. Press the “UPS” button. This brings up a warning dialog box (see Figure 16).
3. Press OK to shut down the UPS
System Shutdown Procedure
1. Press the “Shutdown” menu button on the display touchscreen.
The Shutdown screen will appear in the multipurpose window (see Figure 15).
2. Press the “System” button. This brings up a warning dialog box (see Figure 17).
3. Press OK to shut down the system.
2.6 Automatic Operations
The Liebert NXL UPS system is designed to function while unattended by an operator. The system
control logic monitors the performance of the UPS, the availability of power sources and the current
required by the critical load.
The system control logic:
• Determines what overload conditions can be sustained without a transfer to bypass.
• Initiates an automatic transfer to bypass to sustain an overload or when selected UPS faults
occur.
• Can initiate an automatic retransfer to the UPS after an overload has been cleared.
• Initiates an automatic transfer to bypass and emergency module shutdown when specified UPS
faults occur.
2.6.1 Overloads (Without Transfer)
The UPS system is capable of sustaining full output voltage (±2% of the nominal voltage) for overload
conditions that remain within (under) the current versus time curve of overload capacity (Figure 32).
Note that the time scale is not linear.
For high current demands of short duration (momentary overloads) the critical load is supplied simul-
taneously by both the UPS system and the bypass line. Whenever an overload condition occurs, you
should determine the cause of the overload. If an overload condition exceeds the overload capacity, the
UPS system initiates an automatic load transfer to the bypass line.
NOTE
Service and maintenance work must be performed only by properly trained and qualified
personnel and in accordance with applicable regulations as well as with manufacturers’
specifications.
NOTE
This shutdown turns Off the inverter and the rectifier and trips all battery breakers. Transfers
to bypass if available
NOTE
This shutdown turns Off the inverter and the rectifier and trips all battery breakers. Will shut
down UPS completely.