Emerson Liebert NX 50 and 60 Hz - Manual (Page 29)

Battery Installation
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2.0 B ATTERY I NSTALLATION
2.1 Introduction
The UPS battery bank consists of battery blocks connected in series to provide a D.C. string voltage as
required by the UPS converter. The 'AUTONOMY TIME' (the time during which the battery can
maintain supply to the load in the event of a mains failure) is limited by the ampere-hour capacity of
the battery blocks and in some cases this results in several strings being connected in parallel.
The NX 30-40kVA has internal batteries, but longer run time is available by using an external bat-
tery cabinet.
The battery cabinet will be supplied in one of the following forms:
1. Complete installation, comprising the battery cabinet, batteries and protective device.
2. Battery cabinets and protective device only—batteries supplied by others
3. Battery cabinet only—batteries and circuit breaker supplied by others.
The battery bank may be disconnected from the UPS for maintenance or service. The circuit breaker
can be switched ON or OFF manually and further battery isolation control is achieved through the
use of either a battery circuit-breaker undervoltage coil or through an automatic contactor inside the
UPS.
NOTE
30kVA to 40kVA UPS models contain an internal battery compartment that can accommodate
up to 42 blocks 24 Ah/12V batteries.