Emerson 7400 user manual Starting

Series 7400 Single Phase 1+N UPS

Chapter 2

Operating Instructions

2.1 Introduction

2.1.1Redundant Module System

2.1.2Non - Redundant Module System

2.1.3General Notes

Starting and stopping the one-plus-onesystem is straightforward, however the modules’ response depends on whether it is configured as a Redundant or Non-Redundant system. The operating procedures are the same irrespective of the selected redundancy mode; in simple terms you start (stop) one module and then repeat the operation on the second module.

The difference in the system response concerns the point at which the load is transferred between the bypass and uninterruptible (i.e. inverter) supplies and is summarised below: -

Starting:

When starting a redundant module system the load is transferred from the bypass to the inverter of the first module as soon as the first module is started and its inverter is brought on line. When the second module is started its static bypass line is totally inhibited due to the first module being on line, and the second module will not be connected to the load until its inverter is operational and fully synchronised with the first module.

Stopping:

When the first module is stopped its static bypass is inhibited because the load will be fully maintained by the inverter of the second module. When shutting down the second module, the static bypass lines of both modules will be turned on as soon as its inverter is stopped. That is, both modules will provide load power through their paralleled bypass lines.

Starting:

In a Non-Redundant module system both modules must be running before the load is transferred to their paralleled inverters. Therefore when the first module is started the load will remain connected to its static bypass line.

Stopping:

The load will be transferred to the static bypass lines in both modules simultaneously as soon as the inverter stops in the first module to be shut down.

Note 1: All the user controls and indicators mentioned these in these procedures are identified in chapter 1.

Note 2: The audible alarm may annunicate at various points in these procedures. It can be cancelled at any time by pressing the ‘Alarm Reset’ pushbutton.

Note 3: The 7400 series UPS incorporates an optional automatic boost charge facility which can be used in systems containing non-sealed lead-acid batteries. If this type of battery is used in your installation you may notice that the battery charger voltage will be greater than its nominal 432Vdc when the mains supply returns from a prolonged outage. This is the normal response of the boost charge facility: the charger voltage should return to normal after a few hours.

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