Page 192 - Uninterruptible Power Supplies

Batteries
190 Chapter Seven

Figure 7.4

(PbO) in powder form, is vibrated down these cylinders. This is then
converted to lead dioxide (PbO 2 ), the active material in the cell forma-
tion process. The resultant battery is expensive to produce and clearly
has the same problems as the previous two designs. But it does have
the advantage of being comparatively mechanically robust. The lead-
antimony alloy gives added strength to the plate and this cell has been
in use for traction purposes for many years. Its life depends on the
design/application. Life is affected by the percent of antimony in the
alloy as is the mechanical strength. The use of a low percentage anti-
mony alloy is recommended for UPS applications, for example, 2 to 3
percent. This battery can find uses with UPS systems where physical
conditions preclude the more popular VRLA cells. Such conditions
include deep cycling discharges or large ambient temperature varia-
tions. These conditions can be encountered when designing a UPS sys-
tem for telecommunication equipment that depends on solar and wind
energy as a prime energy source.

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