Eaton 93PM Installation And Operation Manual

Also see for 93PM IBC-L: User and installation guide Manual User and installation guide User and installation guide Installation manual

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Understanding UPS Operation5-2 Eaton 93PM UPS (60–100 kW, 480V) Installation and Operation Manual P-164000227—Rev 2 www.eaton.com/powerquality5.2.1 ModesThe Eaton 93PMUPS supports a critical load in four different modes of operation:l In Energy Saver System (ESS) mode, commercial AC power is supplied directly to the critical load throughthe internal bypass and transfers automatically to Normal mode (double-conversion on demand) if anabnormal condition is detected.l In Normal (double-conversion) mode, the critical load is supplied by the inverter, which derives its powerfrom rectified utility AC power. In this mode, the battery charger also provides charging current for thebattery, if needed.l In Bypass mode, the critical load is directly supported by utility power.l In Battery mode, the battery provides DC power, which maintains inverter operation. The battery supportsthe critical load.The following paragraphs describe the differences in the UPS operating modes, using block diagrams to showthe power flow during each mode of operation.5.2.2 Energy Saver System ModeWhen the UPS is operating in ESS mode, commercial AC power is supplied directly to the critical load throughthe internal bypass with the power module in a standby state. Surge protection and some filtering is alsoprovided, ensuring that clean power is delivered to the load equipment. If a commercial power brownout,blackout, overvoltage, undervoltage, out-of-tolerance frequency condition occurs, or any other disturbance isdetected in the incoming power, the system forward transfers to normal mode (double-conversion on demand).In case of a complete utility outage or if input power is outside the tolerances of the system, the UPS transfersto battery mode and continues to supply conditioned, clean power to the critical load. When the input linereturns to normal operating range, the UPS returns to ESS operation. For charging batteries in ESS mode, theUPS will revert to normal mode to charge the batteries, then return to ESS mode when charge cycle iscomplete.When operating in ESS, the UPS superior detection and control algorithms continuously monitor incomingpower quality and allow the fast engagement of power converters. Typical transition time to double conversionis less than two milliseconds, which is practically seamless. If the UPS detects a fault condition while operatingin ESS, it is also able to detect and determine whether the fault is caused by the load or if it is upstream fromthe UPS. A fault at the bypass source results in an immediate switch over to the inverter; a fault in the loadkeeps the UPS in Energy Saver System (ESS) mode.When power conditions are within acceptable limits, the UPS operates as a high-efficiency, energy-savingsystem — providing surge protection for IT equipment and ensuring clean power is delivered to the facility.Energy saver system increases system efficiency to 99% when supplying 20-100% nominal load, reducingenergy losses by 80%Figure 5-2 shows the path of electrical power through the UPS system when the UPS is operating in Normalmode.ESS mode is a normal operating mode, and not an alarm condition. While the UPS is in this mode, the NORMALlight on the front display will illuminate.