Emerson Liebert NX300 Series User Manual page 18

4 Chapter 1 Overview
This mode supports two configurations: rectifier and bypass adopt two-route mains input, rectifier and bypass adopt
one route input, but this mode does not support maintenance mode.
Figure 1-3 describes the block diagram of the UPS in split bypass configuration (that is, the bypass adopts
independent mains input). In split bypass configuration, the static bypass and maintenance bypass share the same
independent bypass power supply. Where a separate power source is not available for the bypass, the output of
bypass switch Q2 and the main input switch Q1 should be linked to make the bypass input and rectifier input share
the same mains power source.
Note: The main input and bypass input share the same neutral line.
Bypass
power supply
Mains input
2. Two switches
This mode enables the bypass input and main input to share the same mains power source, but does not support
maintenance mode.
Figure 1-4 describes the block diagram of the UPS in common input configuration, the bypass input and main input
share the same mains power source.
Note: The main input and bypass input share the same neutral line.
Bypass
power supply
Figure 1-4 UPS power supply switch configuration (500kVA ~ 600kVA E with two switches)
3. Four switches
This mode enables the rectifier and bypass to adopt two-route mains input configuration and maintenance mode.
Figure 1-5 describes the block diagram of the UPS in split bypass configuration (that is, the bypass adopts
independent mains input). In split bypass configuration, the static bypass and maintenance bypass share the same
independent bypass power supply.
Note: The main input and bypass input share the same neutral line.
During normal operation, all switches except for maintenance switch Q3 should be closed.
NX UPS Single Module And Parallel System 250kVA ~ 800kVA User Manual
No switch option
Rectifier
Battery
BCB
Figure 1-3 UPS power supply switch configuration (500kVA ~ 600kVA E without switch)
Bypass switch Q2
Two switch option
Two switches option
Rectifier
Battery BCB
Static switch
Inverter Static switch
DC bus
Static switch
Inverter Static switch
DC bus
UPS
UPS
output
UPS
UPS
output
Output
switch Q5