Introduction
3Liebert
®
NX
™
1.0 INTRODUCTION
1.1 General 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
DC
Bus
BFB
CB1
(Note 5)
UPS Module
2 Wire +GND
(See Note 2)
3 Wire + GND
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.
To DC Supply
Module Rectifier
AC Input
Module Bypass
AC Input
UPS Output
3 Wire + GND
3 Wire + GND
Critical
Load
