Fig. 5–1. main elements of the ups system – Powerware 9335 User Manual

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Powerware 9335 (80 kVA and 120 kVA) Installation and Operation

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Battery

Charger

Rectifier

EMI Filter

Input Filter

Booster

Contactor

Inverter

Output

Contactor

EMI Filter

Output filter

Output
Switch

IA2

Battery

Static Bypass

Switch

Maintenance

Bypass Switch

IA1

Fig. 5–1. Main Elements of the UPS System

If utility power is interrupted or falls outside the parameters specified in Chapter 13, “Product
Specifications,” the UPS uses a 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 is designed to operate with an alternative power system (such as a generator) or
will shut down your critical load in an orderly manner, if Powerware shutdown software is
used.

In the event of a severe output overload or failure of a critical internal UPS component, an
emergency bypass, consisting of a continuous duty static switch, and backfeed protection
contactor (K4) is utilized. The backfeed protection contactor is located in series with the
static switch, to ensure safety to anyone working upstream of the UPS system. For manual
transfers to bypass, the static switch is also used. The static switch is armed and ready
during both types of transfers.

If maintenance of the UPS system is required, an internal Maintenance Bypass switch
provides a means of isolating the UPS Rectifier/Booster/Inverter components for servicing,
while still supplying power to the critical load.

The operation of the UPS is described in greater detail in the following paragraphs.