very good conductor, non-magnetic and offers con-
siderable resistance atmospheric corrosion. Lightness and resistance corrosion make
aluminium ideal metal for the manufacture cooking pots and food
containers.
good qualities natural rubber flexibility, good insulation and suitability
for use over wide range temperatures.
Aluminium
Aluminium grey-white metal obtained from the mineral bauxite which
is found the United States, Germany and the Russian Federation.3.
Definition
Rubber tough elastic substance
made from the sap tropical plants.8% pure copper, the impurities being extracted from the ore smelting
and electrolysis.
Definition
Synthetic rubber manufactured, as
opposed being produced naturally. For electrical purposes refined about
98. 6.
Copper forms the largest portion the alloy brass, and used the manu-
facture electrical cables, domestic heating systems, refrigerator tubes and
vehicle radiators.
Definition
Silicon rubber Introducing organic
compounds into synthetic rubber
produces good insulating material
such FP200 cables.
Silicon rubber Introducing organic compounds into synthetic rubber pro-
duces good insulating material which flexible over wide range tem-
peratures and which retains its insulating properties even when burned. used the manufacture power cables. The magnesium oxide insulation, copper conductors and
sheath, often additionally manufactured with various external sheaths to
provide further protection from corrosion and weather, produce cable
designed for long-life and high-temperature installations. Special processes and fluxes have now been devel-
oped which allow aluminium welded and soldered.
Magnesium oxide The conductors mineral insulated metal sheathed
(MICC) cables are insulated with compressed magnesium oxide, white
chalk-like substance which heat-resistant and good insulator and lasts
for many years. Copper conductors would too heavy support them-
selves between the pylons.
These properties make ideal for cables used fire alarm installations
such FP200 cables. The overhead cables
of the National Grid are made aluminium conductor reinforced by
a core steel. attractive soft reddish brown metal, copper easily
worked and also used manufacture decorative articles and jewellery. Plug tops, socket outlets and
switch plates are made from this
material. The alloys are cast into cylinder
heads and gearboxes for motorcars, and switch-boxes and luminaires for
electrical installations.
Definition
Magnesium oxide The conductors of
mineral insulated metal sheathed
(MICC) cables are insulated with com-
pressed magnesium oxide
Copper
Copper extracted from ore which mined South Africa, North
America, Australia and Chile.Basic scientific concepts electrotechnology
101
Definition
Thermosetting polymers Once heated
and formed, products made from
thermosetting polymers are fixed
rigidly.
Aluminium alloys retain the corrosion resistance properties pure alu-
minium with increase strength. It
is very good conductor, non-magnetic, offers very good resistance to
atmospheric corrosion and notable for its extreme softness and light-
ness.
. Copper toughens with work,
but may annealed, softened, heating dull red before quenching. However, the
magnesium oxide very hygroscopic, which means that attracts mois-
ture and, therefore, the cable must terminated with special moisture-
excluding seal, shown Fig
