Liebert UPS System user manual Basics, Configuration

Chapter 1 Introduction

Chapter 1 Introduction

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. The UPS also uses the latest in high frequency double conversion 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. The utility source can also power the load through the static bypass. 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.

Figure 1-1 Theory of UPS

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