Liebert UPS System - Manual (Page 11)

Chapter 1 Introduction
5
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Mains output
Bypass
Figure 1-5 Normal mode
2. Battery Mode
When the utility fails, the UPS system will switch to battery mode without
interruption and the battery will power the load through the inverter.
The UPS can return to normal mode automatically when the utility returns to normal,
as shown in Figure 1-6.
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~
output
Bypass
Mains
Figure 1-6 battery mode
3. Bypass Mode
In the event of an inverter overload which last longer than the typical time, an
output short circuit or a fault on the inverter, the UPS will transfer the load to bypass.
There are two kinds of bypass modes. In the first kind, the UPS can be set to
return to normal mode automatically when the fault is cleared. In the second kind,
the UPS is set to return to normal mode only with a manual transfer.
When the main UPS circuit fails, the battery is depleted or a severe fault occurs,
the inverter will be shut down and the system will remain in the bypass mode. The
system can return to normal mode only with a manual reset after the fault is cleared,
as shown in Figure 1-7.
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~ -
Mains
Bypass
output
Figure 1-7 bypass mode