Eaton 9395 UPS (450–825 kVA) Installation and Operation Manual 164201725 Rev 4 www.eaton.com/powerquality 6-1Chapter 6 Understanding UPS Operation6.1 UPS System OverviewThe Eaton 9395 UPS is a continuous-duty, solid‐state, transformerless (at 480 Vac),three-phase, true online system that provides conditioned and uninterruptible ACpower to the UPS system's output and critical load.The basic system consists of a rectifier, battery converter, inverter,monitoring/operation control panel, integrated communication server, and digitalsignal processor (DSP) logic. Figure 6‐1 shows the main elements of the UPS system.If utility power is interrupted or falls outside the parameters specified in Chapter 10,“Product Specifications,” the UPS uses a backup battery supply to maintain power tothe critical load for a specified period of time or until the utility power returns. Forextended power outages, the UPS allows you to either transfer to an alternativepower system (such as a generator) or shut down your critical load in an orderlymanner.OutputContactorK3BatteryBatteryBreakerBatteryConverterInputContactorK1AC Input toRectifier/ChargerAC Input toBypassBackfeedProtectionContactorK5Power ModuleInverterRectifierDigitalMeteringStaticSwitchAC Outputto CriticalLoadUPS CabinetBatteryContactorK2Battery SystemInputBreakerCB1(optional)Bypass Breaker (CB4)NOTE On a UPS configured as an Input Output Module (IOM), the bypass input, static switch, bypass breaker (CB4), andbackfeed protection contactor (K5) are not present.NOTE On a UPS configured with a Continuous Static Switch (CSS), bypass breaker (CB4) is not present.Figure 6‐1. Main Elements of the UPS SystemFigure
