Eaton Power Xpert 9395P-1200 UPS (1200 kVA, 1200 kW) Installation and Operation Manual P-164000500 Rev 4 www.eaton.com/powerquality 6-1Chapter 6 Understanding UPS Operation6.1 UPS System OverviewThe Eaton 9395P-1200 UPS is a continuous-duty, solid‐state, transformerless (at480 Vac), three-phase, true online system that provides conditioned anduninterruptible AC power 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)NOTE On a UPS configured as an Input Output Module (IOM), the bypass input, static switch, and backfeed protectioncontactor (K5) are not present.Figure 6‐1. Main Elements of the UPS SystemThe emergency bypass consists of a continuous static switch, and a backfeedprotection contactor K5. The bypass breaker (if installed) is located in parallel with thestatic switch. The backfeed protection contactor is located in series with the staticswitch. The static switch is armed and ready during normal operation.Figure
