INTRODUCTIONEATON Eaton 9395 550/275 UPS (225–550 kVA) Installation and Operation Manual 164201716 Rev 2 www.eaton.com/powerquality1-61.2.8 Inherent RedundancyTo deliver greater reliability, the Eaton9395 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.1.2.9 Energy Saver System and High Alert ModesNOTE 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 maximizesefficiency by eliminating unnecessary power conversion when the commercial powersource is within acceptable voltage and frequency limits. In this mode, the UPS isactively monitoring the critical bus and instantly and seamlessly transitions todouble-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 ifin double-conversion mode remains in double-conversion mode for a default timeperiod of one hour. High Alert mode allows the user to place the unit indouble-conversion mode when outside conditions could cause a power disturbance.At the completion of the time period, the unit defaults back to ESS mode. If the HighAlert command is received during the time period, the timer will be restarted.1.2.10 Variable Module Management System and High Alert ModesNOTE The Variable Module Management System and Energy Saver System modes are mutually exclusive.The Variable Module Management System (VMMS) mode maintains UPMredundancy and achieves higher efficiencies by intelligently controlling the UPM’sload level. The efficiency rating for each UPM is highest when loads are greater than50% of the system rating. Therefore, shifting the load to fewer UPMs can achievehigher efficiencies when the UPS load is lighter.In VMMS mode, the UPS is actively monitoring the critical bus and UPMs areavailable to assume load in less than 2 ms to respond to load changes.The VMMS feature has three configurable modes of operation: Online mode, Onlinemode with VMMS, and High Alert mode. All modes are selectable from the frontpanel.VMMS mode supports both distributed bypass and SBM parallel configurations.In High Alert mode, all idle UPMs go online for one hour. At the completion of thehour, the UPS defaults back to VMMS mode. If the High Alert command is receivedduring the one hour, the one hour timer will be restarted.
