Eaton 9E - UPS System Overview

Eaton 9E UPS (40–60 kVA, 208/220V) Installation and Operation Manual P-164000058—Rev 4 www.eaton.com/powerquality 5-1
Chapter 5 Understanding UPS Operation
5.1 UPS System Overview
The Eaton 9E UPS is a continuous-duty, solid-state, transformerless, three-phase, true online system that
provides 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 5-1 shows the main elements
of 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
until the utility power returns. For extended power outages, the UPS allows you to either transfer to an
alternative power system (such as a generator) or shut down your critical load in an orderly manner.
Figure 5-1. Main Elements of the UPS System
The emergency bypass consists of a continuous static switch, and a backfeed protection relay. The backfeed
protection relay is located in series with the static switch. The static switch is armed and ready during normal
operation.
AC Input to
Rectifier/
Charger
AC Output
to Critical
Load
Input
Breaker
Input
Relay
Battery
Relay
Battery
Converter
Battery
Output
Relay
UPS Cabinet
Backfeed
Protection
Relay
Static
Switch
Digital
Metering
InverterRectifier
Power Module
AC Input to
Bypass