Drawing
5 - COURSE WIRE ( CW1, CW2, CW3, CW & CW5):-
5 - 1 Purpose:-
Objective of course wire machine is drawing Copper wire or Aluminum wire
from big diameter to small diameter.
Drawing Copper wire has diameter 8mm to many different diameter.
Drawing Aluminum wire has diameter 9 mm or 9.5 mm to many different
diameter.
If decrease in wire diameter then increase in speed of the machine.
If increase in final wire diameter then decrease in dies was used.
5 - 2 Advantage of drawing solution:-
1- Low temperature of mechanic tools.
2- Service life of die.
3- Quality of wire surface.
4- Cooling for die.
5- To making wire to slide inlet dies and capstans (pulleys).
6- Keep the color like sunshine.
5 - 3 How to operate Course Wire machine?
1- Put wire was drawing from upper diameter to different diameters in pointing machine.
2- Put the wire drawing inlet first die and does again steps 1 for second die tell final die (final diameter from final die).
3- Wire drawing passes the annealed and its advantage, the wire after drawing was became hardness and inlet in the annealed to become softness.
4- Take - up:-
a- It has tow spoolers (Tow bobbins).
b- Basket.
5 - 4 Shutdown of machine:-
1- Cut wire.
2- Friction in dies.
3- Friction in pulleys (capstans).
4- Shutdown in dancer.
Sunday, May 23, 2010
CABLE CONSTRUCTION
4 – 3 CABLE CONSTRUCTION:
4 - 3 - 1 Conductor:
-plain copper or aluminum, stranded or solid, circular compacted or sector shaped, all in accordance with IEC 60228.
-no. of wires and wire diameter are adjusted to the specified resistance, so the specification allows the manufacturer to choose the no. and diameter of wires within limits to attain the required specified resistance.
-standard conductor sizes are:
0.5 0.75 1 1.5 2 2.5 4 6 10 16 25 35 50 70 95 120 150 185 240 300 400 500 630 800 1000 1200 1400 1600 2000 2500mm².
Form 0.5 to 2.5mm², are circular compressed conductors.
Form 4 to 35mm², are circular and can be compacted.
Form 50 to 300mm² can either be circular or circular compacted or sector-shaped.
Form 400 to 2000mm², are circular compacted conductors
**sector shaped conductors, mainly used for low voltage cables.
**circular compacted conductors are used for MEDIUM and HIGH VOLTAGE cables.
4 - 3 - 1 Conductor:
-plain copper or aluminum, stranded or solid, circular compacted or sector shaped, all in accordance with IEC 60228.
-no. of wires and wire diameter are adjusted to the specified resistance, so the specification allows the manufacturer to choose the no. and diameter of wires within limits to attain the required specified resistance.
-standard conductor sizes are:
0.5 0.75 1 1.5 2 2.5 4 6 10 16 25 35 50 70 95 120 150 185 240 300 400 500 630 800 1000 1200 1400 1600 2000 2500mm².
Form 0.5 to 2.5mm², are circular compressed conductors.
Form 4 to 35mm², are circular and can be compacted.
Form 50 to 300mm² can either be circular or circular compacted or sector-shaped.
Form 400 to 2000mm², are circular compacted conductors
**sector shaped conductors, mainly used for low voltage cables.
**circular compacted conductors are used for MEDIUM and HIGH VOLTAGE cables.
Classification of cables
Classification of cables:-
4 - 1Classification of cables: cables are usually classified according to the voltage for which they are manufactured accordingly they are classified as:
* Low voltage cables, up to and including 1000 volts.
* Medium voltage cables, starting 2000 volts up to and including 33kv.
* High voltage cables, above 33kv up to and including 150kv.
* Extra high voltage cables, 220kv, 400kv and 500kv.
4 - 2 Requirements for the cables: the followings are the necessary items required for the cables:
-the copper or aluminum conductor should be of correct size suitable for the cable to carry the specified load without overheating the cable, and giving voltage drop within the limits.
-the cores of the cable must have the proper insulation thickness to give high reliability and safety at the voltage for which it is designed.
-the cable must have a mechanical protection so as to withstand the worst conditions of laying and installations.
-all materials used in manufacturing the cable should be stable chemically and physically through out the cable life.
4 - 1Classification of cables: cables are usually classified according to the voltage for which they are manufactured accordingly they are classified as:
* Low voltage cables, up to and including 1000 volts.
* Medium voltage cables, starting 2000 volts up to and including 33kv.
* High voltage cables, above 33kv up to and including 150kv.
* Extra high voltage cables, 220kv, 400kv and 500kv.
4 - 2 Requirements for the cables: the followings are the necessary items required for the cables:
-the copper or aluminum conductor should be of correct size suitable for the cable to carry the specified load without overheating the cable, and giving voltage drop within the limits.
-the cores of the cable must have the proper insulation thickness to give high reliability and safety at the voltage for which it is designed.
-the cable must have a mechanical protection so as to withstand the worst conditions of laying and installations.
-all materials used in manufacturing the cable should be stable chemically and physically through out the cable life.
Factors affecting cable choice 2
1 - Factors affecting cable choice:
2 - 6 Resistivity: it is the resistance offered by the material to the flow of current per unit length, and expressed in ohm / cm².
3 - CONDUCTORS:
-any material supporting current flow is called conductor.
-material of a conductor should have many free electrons, and since metals contain the freest electrons, so metals are the best conductors.
-the common materials used as conductors are: COPPER and ALUMINIUM.
3 - 1 COPPER:
-it is used in cables as a conductor because of its low resistance.
-the common properties of copper as a conductor are:
*resistance of a wire of standard annealed copper, one meter long and of uniform mass section of 1mm² is 0.017241 ohm.
*constant mass temperature coefficient of resistance is 0.00393/cº
*the density is 8.89gm / cm³.
-the international electro-technical commission (IEC) established an international annealed copper standard (IACS) for the resistivity of annealed copper for which the conductivity is equal to 100%.
3 - 2 ALUMINIUM:
-it is commonly used as a conductor since 1945 due to its low cost, good electrical conductivity, good tensile strength, low density and excellent resistance to corrosion.
-it contains a minimum of 99.50% of pure aluminium with a controlled amount of impurities.
-it is usually treated by adding boron to remove titanium, vanadium and zirconium which are harmful to electrical conductivity.
2 - 6 Resistivity: it is the resistance offered by the material to the flow of current per unit length, and expressed in ohm / cm².
3 - CONDUCTORS:
-any material supporting current flow is called conductor.
-material of a conductor should have many free electrons, and since metals contain the freest electrons, so metals are the best conductors.
-the common materials used as conductors are: COPPER and ALUMINIUM.
3 - 1 COPPER:
-it is used in cables as a conductor because of its low resistance.
-the common properties of copper as a conductor are:
*resistance of a wire of standard annealed copper, one meter long and of uniform mass section of 1mm² is 0.017241 ohm.
*constant mass temperature coefficient of resistance is 0.00393/cº
*the density is 8.89gm / cm³.
-the international electro-technical commission (IEC) established an international annealed copper standard (IACS) for the resistivity of annealed copper for which the conductivity is equal to 100%.
3 - 2 ALUMINIUM:
-it is commonly used as a conductor since 1945 due to its low cost, good electrical conductivity, good tensile strength, low density and excellent resistance to corrosion.
-it contains a minimum of 99.50% of pure aluminium with a controlled amount of impurities.
-it is usually treated by adding boron to remove titanium, vanadium and zirconium which are harmful to electrical conductivity.
Factors affecting cable choice
1 - Factors affecting cable choice:
* Application and environment in which the cable will operate.
* Working voltage.
* Load current or max. Rated is current for continuous operation.
* Suitable voltage drop.
* Installation data, in pipes, underground, in air.
* Short circuit current, and time of release.
2 – DEFINITION:
2 - 1 Wire: it is a solid material (copper or aluminum) of certain uniform diameter and uniform cross section, having specified electrical resistance.
2 - 2 Conductor: it is bundle of wires stranded in a specified way and shape having a certain resistance to form a uniform pass-way for electric current. It can be circular or shaped (sect oral).
2 - 3 Core: it is a conductor insulated with a dielectric material (polyvinyl chloride, polyethylene, cross-linked polyethylene, rubber, cellular polyethylene).
2 - 4 Cable: A core or more of cores assembled together, to form single, or multi core cable, to serve in single phase or three phase system.
2 - 5 Resistance: all conductor materials resist the electric current flow. This resistance is directly proportion to the resistivity of conductor material and the conductor length, and inversely proportion to conductor cross-sectional area. It is expressed in “ohm/m”, and is given the symbol “r”
Resistance= resistivity x length / area.
* Application and environment in which the cable will operate.
* Working voltage.
* Load current or max. Rated is current for continuous operation.
* Suitable voltage drop.
* Installation data, in pipes, underground, in air.
* Short circuit current, and time of release.
2 – DEFINITION:
2 - 1 Wire: it is a solid material (copper or aluminum) of certain uniform diameter and uniform cross section, having specified electrical resistance.
2 - 2 Conductor: it is bundle of wires stranded in a specified way and shape having a certain resistance to form a uniform pass-way for electric current. It can be circular or shaped (sect oral).
2 - 3 Core: it is a conductor insulated with a dielectric material (polyvinyl chloride, polyethylene, cross-linked polyethylene, rubber, cellular polyethylene).
2 - 4 Cable: A core or more of cores assembled together, to form single, or multi core cable, to serve in single phase or three phase system.
2 - 5 Resistance: all conductor materials resist the electric current flow. This resistance is directly proportion to the resistivity of conductor material and the conductor length, and inversely proportion to conductor cross-sectional area. It is expressed in “ohm/m”, and is given the symbol “r”
Resistance= resistivity x length / area.
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