Primary cells, the form Leclanche cells, are used extensively por-
table power sources for radios and torches and have emf 1. The batteries contained within these units should replaced about
every years, recommended the manufacturer.
A record should kept each item equipment and the date each
test qualified responsible person.61
The construction lead-acid battery. the cell con-
nected suitable electrical sup-
ply, electrical energy stored the
plates the cell chemical energy.
Self-contained units are suitable for small installations about 12
units. Once the active chemicals are
exhausted, the cell must discarded.
. Thus, supply can
be provided connecting four cells series.61 shows the construction lead-acid battery.5V.
Definition
A secondary cell has the advantage of
being rechargeable.Basic Electrical Installation Work
342
The British Standard recommends that the full load should carried by
the emergency supply for least every months.
Mercury primary cells have emf 1.35V, and can have very large
capacity small physical size.
A lead-acid cell secondary cell.
Once the active chemicals are
exhausted, the cell must discarded. Each cell delivers about 2V, and when
six cells are connected series 12V battery formed the type used on
motor vehicles. They have long shelf life and leakproof
construction, and are used watches and hearing aids. may necessary produce
the record evidence satisfactory compliance with statutory legislation
to duly authorized person. Larger
voltages are achieved connecting cells series.
Negative
connecting bar
Positive
connecting bar
All plates
deeply
ribbed Negative plate
Separator
Positive plate
FIGURE 14. the cell is
connected suitable electrical supply, electrical energy stored the
plates the cell chemical energy. When the cell connected load,
the chemical energy converted electrical energy.
Definition
A primary cell cannot recharged. After testing, the
emergency system must carefully restored its normal operative state.
Secondary cells
A secondary cell has the advantage being rechargeable. Figure 14.
Primary cells
A primary cell cannot recharged
