INTRODUCTIONEaton 9395 UPS (225–275 kVA) Installation and Operation Manual 164201683 Rev 3 www.eaton.com/powerquality 1-51.2.6 Separate Rectifier InputIf a FI-UPM is to be installed with the Eaton 9395 225–275 kVA UPS at the initialinstallation or in the future, the UPS can be supplied with separate rectifier inputs foreach UPM. Separate inputs provide increased flexibility and reliability by allowingmultiple input sources to supply the UPS. Input circuit breaker CB1 is not installedwith this configuration. AC input control to the UPS and each UPM rectifier is to beprovided by the customer.1.2.7 Distributed Bypass SystemThere are two types of redundancy: UPS based (based on the number of UPSs) andUPM 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 acapacity and/or redundant system. This load sharing system provides more capacitythan 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 operatingproperly, a redundant UPM continues to supply uninterrupted power to the criticalload. A Powerware Hot Sync® Controller Area Network (CAN) Bridge Card providesconnectivity and operational mode control. The distributed bypass system consists oftwo to five UPSs each with a parallel CAN card, and a customer-supplied tie cabinet orload 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 auxiliarycontacts for control of the system. Without dual auxiliary MOBs, UPMs are notallowed to go to bypass individually during servicing. All UPMs will go to bypassinstead of just the UPM needing service, decreasing critical load protection. With dualauxiliary MOBs, one UPM can be bypassed while the remaining UPMs support theload as long as the remaining UPMs have the capacity to do so.1.2.8 Inherent RedundancyTo deliver greater reliability, the Eaton 9395 UPS can be configured by an authorizedEaton 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 belowthe capacity of the UPMs minus the capacity of one UPM. Under normal conditionsthe UPMs in the UPS share the load equally. If one or more UPMs becomesunavailable and the load is at or below the capacity of remaining UPMs, the remainingUPMs supply the load instead of transferring to bypass.If the capacity of the UPMs falls below the redundancy level or the load increasesabove redundancy level, but is still able to maintain the load, a loss of redundancyalarm is sounded. If the load exceeds the capacity of remaining UPMs, the UPStransfers to bypass.
