Emerson NX manual General Description, Introduction, UPS Module, Critical Load

Introduction

1.0INTRODUCTION

1.1General Description

The Liebert NX UPS provides continuous, high-quality AC power to your business-critical equipment, such as telecommunications and data processing equipment. The Liebert NX 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 NX 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 to 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

Module Bypass	UPS Module
AC Input
3 Wire + GND	BFB

Module Rectifier		DC
AC Input
3 Wire + GND	CB1	Bus
	(Note 5)

UPS Output

3 Wire + GND

Critical

Load

2 Wire +GND

(See Note 2)

To DC Supply

1.UPS rectifier bypass input and output cables must be run in separate conduits.

2.All power cables from DC supply should be sized for a total maximum of 2V drop at maximum discharge current.

3.Control wiring and power wiring must be run in separate conduits.

4.Emerson recommends installing grounding conductors .

5.Standard configuration has CB1 removed. If CB1 is required, option must be ordered.

3 Liebert®NX™