Chapter 1 Introduction; Basics; Configuration - Liebert UPS System User Manual

1.1 Basics

The Liebert iTrust UPS System is connected between the utility source and the
critical load to provide uninterruptible power to the load. The power from the UPS
being free of voltage and frequency variation and disturbances from utility. The UPS
has an output isolation transformer to provide galvanic isolation between the load
and utility.
PWM technology and a fully digital control.
It also has advanced network management functions.

1.2 Configuration

The UPS consists of the following modules : rectifier, inverter, static bypass,
maintenance bypass, output isolation transformer, inverter static switch, battery and
input and output circuit breakers.
As shown in Figure 1-1, the AC utility source is input at Q1 and the rectifier
converts the AC Utility into DC source. The Inverter will convert the DC source or
the DC source from the batteries into AC source that is output from the isolation
transformer. The battery will power the load through the inverter in case of a power
failure.
Besides this, if maintenance or repair of the UPS is necessary, the UPS can
support the load through the maintenance bypass without interrupting the load.

Chapter 1 Introduction

Chapter 1 Introduction
The UPS also uses the latest in high frequency double conversion
The utility source can also power the load through the static bypass.
Figure 1-1 Theory of UPS
1