Chapter 6

Understanding UPS Operation

6.1UPS System Overview

AC Input to Rectifier/ Charger

AC Input to Bypass

The Powerware 9395 UPS is a continuous−duty, solid-state, transformerless (at 480 Vac), three−phase, true online system that provides conditioned and uninterruptible AC power to the UPS system’s output and critical load.

The basic system consists of a rectifier, battery converter, inverter, monitoring/operation control panel, integrated communication server, and digital signal processor (DSP) logic. Figure 6-1shows the main elements of the UPS system.

Battery

Battery System

Battery

Breaker

 

 

Battery

 

 

Contactor

 

 

K2

 

 

Battery

 

 

Converter

 

Input

 

 

Breaker

Input

Output

CB1

Contactor

Contactor

(optional)

K1

K3

 

Rectifier

Inverter

 

 

Power Module

 

 

 

 

 

 

 

Digital

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Metering

Backfeed

 

 

 

 

 

 

 

 

 

 

 

 

Protection

 

 

 

 

 

 

 

 

 

 

 

 

Contactor

 

 

 

 

 

 

 

Static

 

K5

 

AC Output

 

 

 

 

 

 

 

 

 

 

 

to Critical

 

 

 

 

 

Switch

 

 

 

 

 

 

Load

 

 

 

Bypass Breaker (CB4)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UPS Cabinet

Figure 6-1. Main Elements of the UPS System

If utility power is interrupted or falls outside the parameters specified in Chapter 10, backup battery supply to maintain power to

the critical load for a specified period of time or until the utility power returns. For extended power outages, the UPS allows you to either transfer to an alternative power system (such as a generator) or shut down your critical load in an orderly manner.

The emergency bypass consists of a momentary−duty static switch, a wraparound bypass breaker, and a backfeed protection contactor K5. The bypass breaker is located in parallel with the static switch. The backfeed protection contactor is located in series with the static switch. Bypass breaker CB4 is used for manual transfers to bypass without using the static switch. The static switch is armed and ready during both types of transfers.

EATON Powerware® 9395 UPS (1000–1100 kVA) Installation and Operation Manual S 164201764 Rev 1 www.powerware.com

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Powerware 10001100 kVA operation manual UPS System Overview, Battery System, UPS Cabinet