INTRODUCTIONPower Xpert 9395 UPS (450–550 kVA) Installation and Operation Manual 164201701 Rev 3 www.eaton.com/powerquality 1-51.2.3 Maintenance Bypass ModuleThe Maintenance Bypass Module (MBM) enables power to completely bypass andisolate the UPS so that the UPS can be safely serviced or replaced withoutinterrupting power to critical systems.1.2.4 Sync ControlAn optional Power Xpert 9395 Sync Control maintains the critical load outputs of twoseparate single module Power Xpert 9395 UPS systems in synchronization. Thisoption facilitates the uninterrupted transfer of the load from one load bus to anotherby means of transfer switches. The Sync Control is housed in a wall‐mounted panelthat can be located between the UPS units for easy wiring.1.2.5 Single-Feed KitAn optional kit is available for converting the dual-feed rectifier and bypass inputs to asingle-feed configuration. The kit consists of jumpers and bus bar extenders for eachphase, and the hardware required for installation.1.2.6 Separate Rectifier InputThe Power Xpert 9395 450–550 kVA UPS can be supplied with separate rectifierinputs for each UPM. Separate inputs provide increased flexibility and reliability byallowing multiple input sources to supply the UPS. Input circuit breaker CB1 is notinstalled with this configuration. AC input control to the UPS and each UPM rectifier isto be provided by the customer.All sources that feed the separate rectifier inputs must be from a common groundpoint.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 can contain two to threeUPMs.A distributed bypass UPS system with two to five UPS units can be installed toprovide a capacity and/or redundant system. This load sharing system provides morecapacity than a single UPS, and can provide backup, depending on the load andconfiguration. In addition, when one UPM is taken out of service for maintenance or isnot operating properly, a redundant UPM continues to supply uninterrupted power tothe critical load. A Powerware Hot Sync® Controller Area Network (CAN) Bridge Cardprovides connectivity and operational mode control. The distributed bypass systemconsists of two to five UPS units each with a parallel CAN card, and acustomer-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 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 the just the UPM needing service, decreasing critical load protection. Withdual auxiliary MOBs, one UPM can be bypassed while the remaining UPMs supportthe load as long as the remaining UPMs have the capacity to do so.
