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Operation
58
3.3 Modes of Operation
This section illustrates the flow of power through circuit breakers, switches and UPS components dur-
ing various modes of operation. The same modes of operation apply to all configurations of the Liebert
Series 610 UPS. Highlighted (thick) lines in the diagrams indicate power flow and power availability.
These illustrations show a three-breaker maintenance bypass because it is commonly used. Your
installation may have a two-breaker, three-breaker or four-breaker maintenance bypass or none at all.
These illustrations do not show an alternate power source (generator) and automatic transfer switch
(external to the UPS) that might be present at your installation.
Table 7 below lists abbreviations for circuit breakers used in this manual.
3.3.1 Load on Bypass
Load on Bypass, with the UPS not available, is shown in Figure 41. The UPS system could be in this
mode of operation during either initial start-up or UPS system shutdown and isolation for maintenance.
Figure 41 Load on bypass (UPS not available)
Table 7 Circuit breaker abbreviations
Abbreviation Circuit Breaker
BFB Bypass Feeder Breaker
BIB Bypass Input Breaker
MBB Maintenance Bypass Breaker
MBD Module Battery Disconnect
MIB Maintenance Isolation Breaker
RIB Rectifier Input Breaker
NOTE
When the critical load is being supplied power from the bypass line, it is exposed to utility
power disturbances.
THREE BREAKER MAINTENANCE BYPASS SWITCHBOARD
BIB
MBB
OUTPUT
CB
Rectifier/
Charger
Controls
Battery
Bypass CB
INPUT
CB
Static
Bypass
Switch
CONTROL POWER
UPS MODULE
Inverter
RIB
BFB
MAIN INPUT
SWITCHGEAR
Critical
Load
AC Output
MBD
Static
Switch
Disconnects
MIB