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Eaton 9395XC UPS 1200kW/1200kVA, 1350kW/1350kVA or 1500kW/1500kVA 164001079—Rev 01
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Distributed bypass parallel operation extends the normal operation of 9395XC UPSs by offering increased
capacity and/or redundant capability. The parallel system continues to maintain power to the critical loads
during commercial electrical power brownout, blackout, overvoltage, undervoltage, and out-of-tolerance
frequency conditions.
Communication is required between the UPSs for system metering and mode control. System level
communication and control are accomplished using a Controller Area Network (CAN). A single building alarm in
each UPS, connected to the other UPSs in parallel and tied to the bypass contactor auxiliary contacts in each
UPS, are used for a secondary communication path. This arrangement ensures bypass control even if the CAN
bus is lost.
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Mooddeess
Similar to the single UPS system, the 9395XC UPS parallel system supports a critical load in five different
modes of operation. The standard operation modes are:
•
In Normal mode, the paralleled UPMs supply the critical load with clean, filtered power. Each UPM battery
charger also provides charging current for the battery if needed.
•
In Energy Saver mode, commercial AC power is supplied directly to the critical load through the continuous
static switch and transfers automatically to Online mode if an abnormal condition is detected. The Energy
Saver mode requires a UPS with a continuous static switch. Energy Saver mode in a parallel system
operates the same as it does in a single UPS system (see paragraph
Energy Saver System (ESS) Mode
).
•
In Bypass mode, the critical load is directly supported by utility power through the bypass circuit in each
UPS.
•
In Battery mode, the battery provides DC power, which maintains UPM operation. The UPM batteries
support the critical load.
The UPSs continually monitor themselves and the incoming utility power and automatically switch between
these modes as required, without operator intervention, except when manually switching to Bypass mode. The
sophisticated detection and switching logic inside the UPSs ensures that operating mode changes are
automatic and transparent to the critical load, while internal monitoring systems indicate the current mode of
operation. The UPSs switch operating modes in response to these system events:
•
A
command
is an intervention that is externally initiated by an operator or by some site action. A command
causes the UPSs to switch operating modes; it usually does not require any further action.
•
A
notice
is a minor system event that may or may not require attention.
•
An
alarm
is a system event that requires immediate intervention.
The following paragraphs describe the differences in the parallel system operating modes, using block
diagrams to show the power flow during each mode of operation.
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In Online mode, utility AC power is supplied to the UPSs. Each UPS then conditions the incoming AC power
and provides clean, regulated AC power to tie cabinet or distribution panel for parallel systems up to four
modules. The applied load is shared equally among the available UPMs in the system.
shows the path of electrical power through the parallel system when operating in Online mode.
If the utility AC power is interrupted or is out of specification, the UPSs automatically switch to Battery mode to
support the critical load without interruption. When utility power returns, the UPSs return to Normal mode.
Summary of Contents for 9395XC
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