Chapter 1 Overview 5
Liebert NXC 30kVA And 40kVA UPS User Manual
4. For parallel system consists of two or more UPS modules, the bypass load sharing inductors (optional) should be
selected.
1.4 Operation Modes
The UPS has the following operation modes:
Normal mode
Battery mode
Automatic restart mode
Bypass mode
Maintenance mode
ECO mode
Parallel redundancy mode (system expansion)
LBS system mode
Common battery string mode
Normal mode
As shown in Figure 1-3, the mains is rectified by the UPS rectifier and then inverted by the inverter to supply
uninterrupted AC power to the loads. At the same time, the charger will charge the battery.
Figure 1-3 Schematic diagram of normal mode
Battery mode
As shown in Figure 1-4, the operation mode in which the battery provides backup power supply to the loads through
the rectifier and inverter is called battery mode. Upon mains failure, the system will automatically transfer to the battery
mode with no load power interruption. When the mains is recovered, the system will automatically transfer back to the
normal mode without any manual intervention, and the power to the load will not be interrupted.
Figure 1-4 Schematic diagram of battery mode
Note: Battery cold start function is available for switching the UPS on from Battery (charged) mode directly during
mains failure. Therefore, the battery power supply can be used independently to improve the availability of the UPS.
Automatic restart mode
The UPS has automatic restart function. When the inverter shuts down because the mains fails and the battery
discharges to EOD voltage, if the mains is recovered, the UPS will restart automatically after a certain time of delay.
This function and the automatic restart type can be set by the service engineer authorized by Emerson.
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