Vertiv Tech EXS 0080kTK16FN01000, User Manual

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Vertiv | Liebert EXS 80kVA UPS | User Manual 3
Overview
3. When the mains is abnormal:
i. The rectifier/PFC circuit boosts the battery voltage and supplies it to the inverter.
ii. The inverter then converts it into pure sine wave AC power and supplies the AC power to the load. If the
battery voltage drops to End of Discharge (EOD) voltage and the mains is still not recovered, the UPS will shut
down (if the system uses split bypass configuration and the bypass is normal, the system will be transfered to
bypass). The battery EOD voltage is preset.
iii. The battery maintains the UPS operation until the battery voltage is reduced to EOD voltage and the UPS
shuts down, this time is called ‘Backup Time’. The length of backup time depends on the battery capacity and
the loads.
4. After the mains returns to normal state, the UPS automatically transfers from Battery mode to Normal mode,
and the rectifier and inverter work together to supply the loads and charge the battery.
1.2.2. Bypass
The loads can be supplied by the inverter or the bypass through the intelligent control of the ‘Bypass Automatic
Switch ’ (as shown in Figure 1-1 ). In normal circumstances, the loads are supplied by the inverter, in which case the
automatic inverter switch is closed at inverter side. In the event of overload (the overload delay time expires) or
inverter failure, the automatic inverter switch is opened, and the ‘ Bypass Automatic Switch ‘ module automatically
transfers the loads to the bypass.
In normal operating state, the inverter output must be fully synchronized with the bypass to realize the
uninterrupted transfer between inverter and bypass.
Therefore, when the bypass frequency is within the synchronization range, the inverter control circuit synchronizes
the inverter output frequency with the bypass frequency and phase.
In addition, the UPS has a manual maintenance bypass switch to shutdown the UPS during maintenance. In this
situation, the bypass supplies the critical loads directly through the maintenance bypass.
• When the load is supplied by the bypass or maintenance bypass, the power supply quality will be
uncertain.