OPERATIONEaton 9315/9390/9395 Fixed Master Sync Control Installation and Operation Manual P-164000023 Rev 1 www.eaton.com/powerquality4-2When the two bypass sources regain availability and synchronization, the Eaton FixedMaster Sync Control provides the non-master system with its own bypass sensingvoltage as a synchronization reference. Before resynchronization occurs, a 15-secondpreset time delay ensures the two bypass sources maintain acceptablesynchronization.To maintain a fault-tolerant arrangement, the Eaton Fixed Master Sync Controlaccounts for the following fault conditions or abnormal operating conditions: When the non-master system is synchronized to the master source, a transfer tobypass disable signal is sent to the non-master system. This inhibits any transfersto bypass on the non-master system If one UPS system loses its critical load bus voltage sensing, the non-mastersystem synchronizes to its own bypass source. Dual redundant logic power supplies are incorporated within the Eaton FixedMaster Sync Control, ensuring both systems remain synchronized even during theloss of one of the logic power supplies. If one or both power supplies fail, an alarmis sent back to the slave system indicating a “SYNC CONTROL TROUBLE” alarm.These power supplies are powered from each system's critical load bus. With a complete loss of logic power to the Eaton Fixed Master Sync Control (dueto component failure or power supply fault), the non-master system synchronizesto its own bypass source.NOTE The Synchronization Reference Control relays are shown under normal conditions.NOTE Dashed switch position of Synchronization Reference Control Relay 1 shows UPS in the non-master system mode.(non-master)UPSBypassVoltageMasterSystemOutputVoltageUPSSYNCHRONIZATIONREFERENCEVOLTAGEEATONFIXED MASTER SYNCCONTROLSYNCHRONIZATIONREFERENCECONTROL RELAYRELAYFigure 4‐1. Synchronization Reference Control
