Thermosetting polymers Once heated and formed, products made from
thermosetting polymers are fixed rigidly.
Synthetic rubber manufactured, opposed being produced natu-
rally.
Definition
Ferrous word used describe all
metals which the main constituent
is iron.
They are good insulators, but give off toxic fumes when burned.
Ferrous word used describe all metals which the main constituent
is iron.
These electrons can easily become
‘free electrons’ which allows heat and
electricity pass easily through the
material. Brass alloy cop-
per and zinc, usually the ratio 70–30% 60–40%.
An insulator material, usually non-metal, which the electrons are
very firmly bound the nucleus and, therefore, will not allow heat elec-
tricity pass through it.
Definition
A conductor material, usually a
metal, which the electrons are
loosely bound the central nucleus.
It good insulator, but degrades and becomes brittle when exposed to
sunlight. Synthetic artificial rubber carefully manufactured have all the
.
Rubber tough elastic substance made from the sap tropical plants. They
are non-magnetic and resist rusting.
Corrosion The destruction metal chemical action.
A conductor material, usually metal, which the electrons are
loosely bound the central nucleus. Let now define the terms and properties some the materials used
in the electrotechnical industry. Copper, aluminium, tin, lead, zinc
and brass are examples non-ferrous metals.
Ferrous metals have magnetic properties. Plug tops, socket outlets and
switch plates are made from this material.
Definition
Corrosion The destruction metal
by chemical action. Most corrosion
takes place when metal contact with moisture (see also mild steel
and zinc).
All materials are made atoms and electrons.
Non-ferrous Metals which not contain iron are called non-ferrous.
Definition
Non-ferrous Metals which not con-
tain iron are called non-ferrous. 4. Cast iron, wrought iron and steel
are all ferrous metals. The word ‘ferrous’ comes from the Latin word ferrum meaning iron.
Definition
An insulator material, usually a
non metal, which the electrons are
very firmly bound the nucleus and,
therefore, will not allow heat elec-
tricity pass through it. These electrons can easily become
‘free electrons’ which allows heat and electricity pass easily through the
material. What makes them differ-
ent materials the way which the atoms and electrons are arranged and
how strongly the electrons are attracted the atoms.1 the last chapter looked the atomic structure materials.
Definition
Thermoplastic polymers These may be
repeatedly warmed and cooled with-
out appreciable changes occurring in
the properties the material.Basic Electrical Installation Work
100
Properties conductors and insulators
In Fig.
Definition
Alloy alloy mixture two or
more metals.
Definition
Polyvinylchloride (PVC) used for cable
insulation thermoplastic polymer. Polyvinylchloride (PVC) used for cable insulation thermo-
plastic polymer.
Thermoplastic polymers These may repeatedly warmed and cooled
without appreciable changes occurring the properties the material. They have
a flexible quality when operated maximum temperature 70°C but
should not flexed when the air temperature near 0°C, otherwise they
may crack. Alloy alloy mixture two more metals
