Eaton 93PM UPS (400V/480V Four-Wire – 100 kW Frame) Installation and Operation Manual 164000566—Rev 04 87CChhaapptteerr 55 UUnnddeerrssttaannddiinngg UUPPSS OOppeerraattiioonn55..11 UUPPSS SSyysstteemm OOvveerrvviieewwThe Eaton 93PM UPS is a continuous-duty, solid-state, transformerless, three-phase, true online system thatprovides conditioned and uninterruptible 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 digital signal processor (DSP) logic. Figure 38 shows the main elementsof the UPS system.If utility power is interrupted or falls outside the parameters specified in Chapter 9 Product Specifications,the UPS uses a backup battery supply to maintain power to the critical load for a specified period of time or untilthe utility power returns. For extended 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 orderly manner.The emergency bypass consists of a continuous static switch, and bypass switchgear. The bypass switchgearis located in series with the static switch. The static switch is armed and ready during normal operation.This unit is a three-wire device. The loss of a single input phase will be considered a complete loss of inputpower and discharge the battery to provide power to the load.Figure 38. Main Elements of the UPS SystemBatteryUPS CabinetBatterySwitchgearInverterSwitchgearBypassSwitchgearPower ModuleRectifierSwitchgearAC Input toRectifier/ChargerAC Input toBypassAC Outputto CriticalLoadDigitalMeteringStaticSwitchBatteryConverter
