Properties of Aluminium and ACSR Conductor
Aluminium is a very malleable and ductile metal with a soft white colour. It's melting and boiling points are 655°C and 2057°C, respectively. At 20 degrees Celsius, it has a density of 2.7 gmm / square centimetre. Pure aluminium has a thermal conductivity of 0.503 cal/cm sec/°C. At 20 degrees Celsius, it has a temperature coefficient of 0.0035 per °C. 2.8 x 10-8 ohm-m is its resistivity. It has a high corrosion resistance as well as a high resistance to touch. Its tensile strength ranges from 0.95 to 1.57 tonnes per square centimetre and it cannot be soldered. When exposed to air, an oxide layer forms, with a tensile strength of 9 kg / sq.mm. Aluminium alloys include the following:
(a) Aldrey (b) Duraluminium (c) Hindalium (d) Magnelium
1. Aldrey :
Aldrey is a magnesium
alloy with 0.3 to 0.5 % magnesium, 0.4 to 0.7 % silicon, and 0.2 to 0.3 %
iron. It has high conductivity and is mechanically strong. This alloy is
utilised in the construction of small and medium-distance overhead transmission
lines. The following are the alloy's physical properties:
Tensile strength 32 to 37 kg / mm2
Specific gravity 2.7 gm
/ cm2
Melting point 1100°C
2. Duraluminium:
It is made up of 4.22 % copper, 0.65 % manganese, 0.54 % magnesium, 0.22 % silicon, 0.42 % iron, and the balance is aluminium. The alloy is castable and is used to make the conductors and end rings of a squirrel cage induction motor's rotor. Because it is non-magnetic, light, and machining-friendly, it is also utilised for bus-bar castings in a switch gear. Bow Pantograph assembly is made of an aluminium alloy with 2.5 % to 6% copper because of its low inertia, good electrical conductivity, and mechanical strength. This can also be done with Aldrey.
3. Hindalium :
It's a brand name for an
alloy including Al, Mg, Mn, Cr, and Si, etc. It is primarily produced as a 16
gauge rolled product for anodized utensil manufacturers.
4. Magnelium :
It's made up of 0 to %
Cu, 1 to % Mg, 0-1.2 % Ni, 0.3 % Sn, 0.9 % Fe, 0 to 0.03
% Mn, 0.2 to 0.6 Si, and 85 to 95% Al. It's a brittle, lightweight alloy
with poor castability. Welding and machining are both possible with this
material. It is primarily employed in the aerospace and automobile industries
for vehicle door handles, the largest racks, and gearbox housing, among other
applications.
ACSR CONDUCTOR :
|
ACSR Conductor |
The ACSR Conductor is explained in the figure. ACSR stands for Aluminium Conductor Steel Reinforced. It has a galvanised steel wire central core and one or more layers of stranded aluminium wires on the outside. Such a conductor has a much higher ultimate tensile strength than analogous copper conductors while yet weighing around 25% less. Due to its lighter weight and strong tensile strength, this conductor has less sag. It's utilised for transmission lines with a span of above 100 metres.
Physical Properties of A.C.S.R.Conductors:
|
x 1 : 6 |
x 1 : 4 |
|
|
Specific gravity |
3.45 |
3.7 |
|
Young's Modulus in kgf/mm2 |
7.5 |
8.3 |
|
Ultimate strength in kgf/ mm2 |
120 |
120 |
x is the ratio of the cross-section
area of iron to aluminium.