Eaton 93E MK2 Installation And Operation Manual

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5.2 Single UPSA single UPS operates independently to support an applied load from the inverter, providingconditioned and uninterruptible AC power to the critical load from the output of the module. Duringan outage, the inverter continues to operate, supporting power to the load from the battery supply. Ifthe unit requires service, applied loads are transferred to the internal bypass either automatically ormanually. With the exception of an optional external battery cabinet, no other cabinets or equipment arerequired for the single UPS to successfully support its applied loads.5.2.1 ModesThe Eaton 93E MK2 UPS supports a critical load in four different modes of operation:• In Standard Normal mode, the critical load is supplied by the inverter, which derives its power fromrectified utility AC power. In this mode, the battery charger also provides charging current for thebattery, if needed, Standard mode is the standard normal operating mode.• In High-Efficiency (HE) mode, commercial AC power is supplied directly to the critical loadthrough the internal bypass and transfers automatically to Standard Normal mode (double-conversion on demand) if an abnormal condition is detected.Note：Need to enable HE mode from LCD• In Bypass mode, the critical load is directly supported by utility power.• In Battery mode, the battery provides DC power, which maintains inverter operation. The batterysupports the critical load.The following paragraphs describe the differences in the UPS operating modes, using block diagrams toshow the power flow during each mode of operation.5.2.2 High-Efficiency ModeWhen the UPS is operating in HE mode, commercial AC power is supplied directly to the critical load throughthe internal bypass with the power module in a st andby st ate. If a commercial power brownout, blackout,over volt age, under voltage, or out-of-tolerance frequency condition occurs the system forward transfers tonormal mode (double-conversion on demand) or battery mode. When the input line returns to normal operatingrange, the UPS returns to HE operation. For charging batteries in HE mode, the UPS will revert to normalmode to charge the batteries, then return to HE mode when charge cycle is complete.HE mode, if selected, is a normal operating mode, and not an alarm condition. While the UPS is in thismode, the NORMAL light on the front display will illuminate.5.2.3 Standard Normal ModeDuring Standard Normal mode, power for the system is derived from a utility input source through therectifier input cont actor. Three-phase AC input power is converted to DC using IGBT devices to producea regulated DC voltage to the inverter. When the battery contactor is closed the battery is chargeddirectly from the regulated rectifier output through a buck or boost DC converter, depending on thesystem voltage and the size of the battery string attached to the unit.Figure 5-2 shows the path of electrical power through the UPS system when the UPS is operating inNormal mode.The battery converter derives its input from the regulated DC output of the rectifier and provides eithera boosted or bucked regulated DC voltage charge current to the batter y. The battery is alwaysconnected to the UPS and ready to support the inverter should the utility input become unavailable.The inverter produces a three-phase AC output to a customer's load without the use of a transformer.The inverter derives regulated DC from the rectifier and uses IGBT devices and pulse-widthmodulation (PWM) to produce a regulated and filtered AC output. The AC output of the inverter isdelivered to the system output through the output cont actor.41Eaton 93E MK2 UPS (10-40kVA, 380/400/415V) Installation and Operation