Liebert UPS System - Manual (Page 13)

Chapter 1 Introduction
7
6. United Power Mode
When the utility is not available and the capacity of the generator set is inadequate
to support the load, the battery will power the load together with the generator
automatically. The operating time under this mode should not exceed the autonomy
time of the batteries, as shown in Figure 1-10
Note :
This mode can only be set by qualified personnel only.
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output Mains
Bypass
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Figure 1-10
7. Parallel Operation mode
When several UPS units (maximum four units) are in parallel operation mode, they
will share the load automatically amongst themselves. If one unit fails, this unit will
be shut down automatically and the remaining units will share the load equally. If
overload occurs, the UPS will transfer to bypass operation mode. Parallel operation
mode also has normal mode, battery mode, bypass mode, maintenance mode and
united power mode.
8. Dual Input Mode
The main circuit and the bypass can use the same or different sources. The input
methods are shown in Figure 1-11 and Figure 1-12.
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Mains output
Fig 1-11