Eaton Power Xpert 9395 550/275 Installation And Operation Manual page 26

All sources that feed the separate rectifier inputs must be from a common ground point.
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There are two types of redundancy: UPS based (based on the number of UPSs) and UPM based (based on the
number of UPMs). Each UPS contains one or two UPMs.
A distributed bypass UPS system with two to five UPSs can be installed to provide a capacity and/or redundant
system. This load sharing system provides more capacity than a single UPS, and can provide backup,
depending on the load and configuration. In addition, when one UPM is taken out of service for maintenance or
is not operating properly, a redundant UPM continues to supply uninterrupted power to the critical load. A
Powerware Hot Sync ® Controller Area Network (CAN) Bridge Card provides connectivity and operational mode
control. The distributed bypass system consists of two to five UPSs each with a parallel CAN card, and a
customer-supplied tie cabinet or load distribution panel to act as a tie point.
All UPSs in the distributed bypass system must contain the same number of UPMs. Mixed UPS kVA ratings are
not permitted.
The tie cabinet must contain Module Output Breakers (MOBs) with dual auxiliary contacts for control of the
system. Without dual auxiliary MOBs, UPMs are not allowed to go to bypass individually during servicing. All
UPMs will go to bypass instead of just the UPM needing service, decreasing critical load protection. With dual
auxiliary MOBs, one UPM can be bypassed while the remaining UPMs support the load as long as the
remaining UPMs have the capacity to do so.
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The UPS can be supplied in an Input Output Module (IOM) configuration without the bypass input connections,
the static switch, the motorized wraparound bypass breaker, and the backfeed protection contactor. This
configuration is primarily used in multiple UPS parallel systems that do not need a bypass for each UPS and use
a separate System Bypass Module (SBM) to provide system bypass capabilities.
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To deliver greater reliability, the Power Xpert 9395 UPS can be configured by an authorized Eaton Customer
Service Engineer for inherent redundancy. When configured, the UPS automatically becomes redundant if the
load is at or below the capacity of the UPMs minus the capacity of one UPM. Under normal conditions the
UPMs in the UPS share the load equally. If one or more UPMs becomes unavailable and the load is at or below
the capacity of remaining UPMs, the remaining UPMs supply the load instead of transferring to bypass.
If the capacity of the UPMs falls below the redundancy level or the load increases above redundancy level, but
is still able to maintain the load, a loss of redundancy alarm is sounded. If the load exceeds the capacity of
remaining UPMs, the UPS transfers to bypass.
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NOTE Energy Saver System mode requires the UPS to be factory built with a Continuous Static
Switch (CSS).
NOTE The Variable Module Management System and Energy Saver System modes are
mutually exclusive.
As a subset of Online mode, the Energy Saver System (ESS) mode maximizes efficiency by eliminating
unnecessary power conversion when the commercial power source is within acceptable voltage and frequency
limits. In this mode, the UPS is actively monitoring the critical bus and instantly and seamlessly transitions to
double-conversion mode (inverter online) if a commercial electrical power brownout, blackout, overvoltage,
undervoltage, or out–of–tolerance frequency condition occurs.
In High Alert mode the unit transfers from ESS mode to double-conversion mode or if in double-conversion
mode remains in double-conversion mode for a default time period of one hour. High Alert mode allows the
Eaton Power Xpert 9395 UPS Installation and Operation Manual 164201716—Rev 14
Introduction
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