Introduction; General Description; Figure 1 Typical Single Module Ups System One-Line Diagram - Emerson Liebert NXL 250 kVA Operation And Maintenance Manual

1.0 I
NTRODUCTION
1.1

General Description

The Liebert NXL UPS provides continuous, high-quality AC power to your business-critical
equipment, such as telecommunications and data processing equipment. The Liebert NXL UPS
supplies power that is free of the disturbances and variations in voltage and frequency common to
utility power, which is subject to brownouts, blackouts, surges and sags.
The Liebert NXL utilizes the latest in high-frequency, double-conversion pulse-width modulation
technology and fully digital controls to enhance its reliability and increase the ease of use.
As shown in Figure 1, the AC utility source is input at CB1 and the rectifier converts the AC utility
into DC power. The inverter converts that DC power from the utility—or DC power from the DC
source— into AC power for the load. The DC source will power the load through the inverter in the
event of a power failure. The utility source can also power the load through the static bypass.
If maintenance or repair of the UPS is necessary, the load can be switched without interruption in
service to the optional maintenance bypass.
Figure 1 Typical single module UPS system one-line diagram
Bypass
Input
CB1
DC Source
® ™
Liebert NXL
BFB
DC Bus
MBD
2

Introduction

Module
Output
CB2