INTRODUCTION
Eaton 9395 UPS (225–275 kVA) Installation and Operation Manual S 164201683 Rev 3 www.eaton.com/powerquality
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1.2.6 Separate Rectifier Input
If a FI-UPM is to be installed with the Eaton 9395 225–275 kVA UPS at the initial
installation or in the future, the UPS can be supplied with separate rectifier inputs for
each UPM. Separate inputs provide increased flexibility and reliability by allowing
multiple input sources to supply the UPS. Input circuit breaker CB1 is not installed
with this configuration. AC input control to the UPS and each UPM rectifier is to be
provided by the customer.
1.2.7 Distributed Bypass System
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.
1.2.8 Inherent Redundancy
To deliver greater reliability, the Eaton 9395 UPS can be configured by an authorized
Eaton Customer Service Engineer for inherent redundancy if a FI-UPM is installed.
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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