Liebert 610 - Manual (Page 65)

Operation
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3.3.2 OK to Transfer
The OK to Transfer status message will be displayed when the bypass line and UPS output power are
both available, their voltage, frequency and phase synchronization are matched within specifications,
and the Static Switch Disconnects are closed (ON). An alarm message may be displayed to indicate
Load On Bypass (Figure 42). If no alarm is displayed, the operating status is Load On UPS
(Figure 43).
When the OK to Transfer message is displayed, you can perform a manual transfer of the load from
the UPS system to bypass or a manual retransfer of the load from bypass to the UPS system.
Use the Load Transfer Procedures screen when performing a manual transfer. Refer to 3.4.2 - Load
Transfer Procedures.
Figure 42 Load on bypass (UPS available)
The UPS system control logic will initiate an automatic transfer to bypass if an overload condition
exceeds the system current versus time window or if a UPS fault is detected. An automatic retransfer
to the UPS system may be initiated when recovering from system overloads lasting less than five min-
utes. Refer to 3.5 - Automatic Operations.
OUTPUT
CB
Rectifier/
Charger
Controls
Battery
Bypass CB
INPUT
CB
Static
Bypass
Switch
Inverter
RIB
BFB
Critical
Load
AC Output
MBD
Static
Switch
Disconnects
THREE BREAKER MAINTENANCE BYPASS SWITCHBOARD
CONTROL POWER
UPS MODULE
MAIN INPUT
SWITCHGEAR
BIB
MBB
MIB