Eaton 9395XC UPS 1200kW/1200kVA, 1350kW/1350kVA or 1500kW/1500kVA 164001079—Rev 01
95
this operating mode until the input power to the rectifier is again within the specified voltage or frequency
acceptance windows.
If the input power fails to return or is not within the acceptance windows required for normal operation, the
battery continues discharging until a DC voltage level is reached where the inverter output can no longer
support the shared loads. When this event occurs, each UPS issues another set of audible and visual alarms
that indicate a two-minute SHUTDOWN IMMINENT warning. Unless the system has a valid AC input soon,
redundant UPMs begin shutting down until there are no longer enough UPMs online to support the connected
load. When this event occurs, the system shuts down. If the bypass source is available, the system transfers to
bypass instead of shutting down.
Figure 53. Path of Current through the UPSs in Battery Mode – Distributed Bypass
Main Power Flow
UPS 1
UPS 2
Output to
Critical Load
Battery
UPS Input
Tie Cabinet
UPS 1 Output
UPS 2 Output
Battery
Closed
Open
Breakers
If at any time during the battery discharge the input power becomes available again, the rectifier begins to
supply DC current to the inverter. At this point, the UPS returns to Normal mode. If at any time during the
battery discharge the AC input power becomes available again, each rectifier turns on, assumes the inverter
load from the batteries, and begins recharging the batteries. Depending on the total load and the duration of the
battery discharge, battery and rectifier input current limit alarms may be seen for a short time due to the current
required to recharge the batteries.
66..55
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PS
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The distributed bypass system oneline drawings in this section show the simplified internal structure of the
UPS, battery supply, and basic maintenance bypass in a multiple UPS configuration. These onelines represent
each UPS in the distributed bypass system.
Summary of Contents for 9395XC
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