Operating instructions

Eaton 9E UPS (40–60 kVA, 208/220V) Generation 3 Installation and Operation Manual P-164000302—Rev 1 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 bypass switchgear. The bypass switchgear
is located in series with the static switch. The static switch is armed and ready during normal operation.
5.2 Single UPS
A single UPS operates independently to support an applied load from the inverter, providing conditioned and
uninterruptible AC power to the critical load from the output of the module. During an outage, the inverter
continues to operate, supporting power to the load from the battery supply. If the unit requires service, applied
loads are transferred to the internal bypass either automatically or manually. With the exception of an optional
external battery cabinet, no other cabinets or equipment are required for the single UPS to successfully support
its applied loads.
AC Input to
Rectifier/
Charger
AC Output
to Critical
Load
Input
Breaker
Rectifier
Switchgear
Battery
Switchgear
Battery
Converter
Battery
Inverter
Switchgear
UPS Cabinet
Bypass
Switchgear
Static
Switch
Digital
Metering
InverterRectifier
Power Module
AC Input to
Bypass