Page 193 - Uninterruptible Power Supplies

Batteries
Batteries 191

Figure 7.5 Pasted plate.

All cells having flooded-type electrolyte construction clearly require
a vent plug for each cell to allow release of gases, electrolyte replenish-
ment, and access for measuring specific gravity and to inhibit acidic
electrolyte spray. Basic designs are simple threaded plugs with a
labyrinth construction inhibiting spray. There are designs, which in
addition, enclose a small float indicating electrolyte level. Others may
include a special flameproof feature and a small catalytic converter
enabling exhaust gases to be reconverted to water, thus reducing the
need to replenish electrolyte. Also, automatic refilling systems con-
nected to a central electrolyte reservoir are available.

VRLA Types and Characteristics
The lead acid battery in most demand for utilization with UPS systems
is undoubtedly the valve regulated type. The design was borne of a
desire to provide an alternative battery for the telecommunications
trade. Their desire was to break away from the very large central bat-
tery system and use smaller battery configurations for use with more
numerous but smaller switching centers, The immediate design criteria

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