3.2
OPERATION OVERVIEW
The UPS provides two power paths between the utility source and the critical load.
Figure 3-1 shows the path for normal operation, with the load powered by the inverter.
Figure 3-2 shows the path for bypass operation, with the load supplied through the static bypass line.
3.2.1
Normal operation: Load power supplied by each system UPS inverter.
CB
Bypass
Input
User supplied
MCCB
CB
AC
Input
User supplied
MCCB
CB2
External
Battery
Cabinet
Battery
Figure 3-1 Single Line Diagram – Normal Operation: Load powered by UPS inverter
During normal operation, the path through the UPS inverter is used to power the load.
In Figure 3-1 input AC power is converted to DC by the Converter. DC power is utilized to charge the
UPS battery and to provide power to the Inverter. The Inverter converts the DC power to clean AC power
to supply the critical load.
The conversion - inversion process eliminates any voltage transients or fluctuations existing in the
input power before it reaches the critical load.
The power drawn by the critical load is equally shared between all UPS systems when multiple UPSs
are in Parallel Operation. (Figure 5-12 shows a sample of Parallel Operation System Configuration.)
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CB3
CONVERTER
CB1
CHARGER
UPS Module
52S
Static Transfer
Switch
INVERTER
52C
Power Flow
Not in Use
CB
Output