Understanding Ups Operation; Ups System Overview; Figure 6-1. Main Elements Of The Ups System - Eaton Power Xpert 9395P-900 Series Installation And Operation Manual

Chapter 6

Understanding UPS Operation

6.1

UPS System Overview

The Eaton Power Xpert 9395P-900 UPS is a continuous-duty, solid-state, transformerless (at 480 Vac),
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 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 to the critical load for a specified period of time or
until the utility power returns. For extended power outages, the UPS system allows you to either transfer to an
alternative power system (such as a generator) or shut down your critical load in an orderly manner.
AC Input to
Rectifier/
Charger
AC Input to
Bypass
NOTE On a UPS configured as an Input Output Module (IOM), the bypass input, static switch, and backfeed protection
contactor (K5) are not present.

Figure 6-1. Main Elements of the UPS System

The emergency bypass consists of a continuous static switch, and a backfeed protection contactor K5. The
bypass breaker (if installed) is located in parallel with the static switch. The backfeed protection contactor is
located in series with the static switch. The static switch is armed and ready during normal operation.
Eaton
Battery System
Input
Breaker
Input
CB1
Contactor
(optional)
K1
® ®
Power Xpert 9395P-900 UPS Installation and Operation Manual P-164000501—Rev 09
Battery
Battery
Breaker
Battery
Contactor
K2
Battery
Converter
Rectifier Inverter
Power Module
Digital
Metering
Backfeed
Protection
Contactor
Static
Switch
UPS Cabinet
Output
Contactor
K3
K5
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AC Output
to Critical
Load
6-1