Copper clad aluminum cable definition:
Copper clad aluminum cable refers to the copper layer which is the main body of the cable instead of copper.
For mechanical and electrical installation industry, wire and cable in mechanical and electrical installation project occupies the important position, as its main raw materials of copper, accounted for 70% ~ 80% of the total cost of cable products, the price of copper cables with copper prices rose sharply, to the construction of the investors and brings great difficulties in the project cost control, therefore, research and application of copper clad aluminum cable to grow rapidly.
The above introduces the definition of copper clad aluminum cable, and then we will discuss the classification of copper clad aluminum cable and the characteristics of copper clad aluminum cable:
The copper clad aluminum cable is used to replace copper as the main body, and the copper layer of the outer bread is a certain proportion of the cable.
The copper clad aluminum cable is divided into two types: one is the copper clad aluminum cable for signal or communication purpose, and the other is the copper clad aluminum cable for power supply.
In terms of its characteristics, copper clad aluminum and pure copper cable are compared.
1. Copper clad aluminum communication cable.
The strength and elongation ratio of pure copper conductor is greater than that of copper clad aluminum conductor, which means that pure copper is better than copper clad in mechanical properties.
From the perspective of cable design, the mechanical strength of pure copper conductor is better than that of copper clad aluminum conductor, which is not necessary in practical application.
The copper clad aluminum conductor is much lighter than the pure copper, so the cable of the copper clad aluminum is lighter than the pure copper conductor cable in overall weight, which will bring convenience to the transportation of the cable and the erection of the cable.
In addition, copper clad aluminum is a little softer than pure copper, and the cable produced by copper clad aluminum conductor is a bit better than the pure copper cable in terms of softness.
Because poor than copper, the conductivity of aluminium made of copper clad aluminum conductor dc resistance than pure copper conductor, this presence of influence mainly to see if the cable will be used to power supply, such as supplies power to the amplifier, if be used to power supply, copper clad aluminum conductor will lead to additional power consumption, voltage lower more.
When the frequency exceeds 5MHz, the ac resistance attenuation at this time is not significantly different between the two different conductors.
Of course, this is mainly because the skin effect of high frequency current, the higher the frequency, the flow of electric current is more close to the conductor surface, on the surface of copper clad aluminum conductor in pure copper material, at some point when the frequency is high, the current to flow in copper plating quality inside.
In the case of 5MHz, the current flows in the approximately 0.025mm thickness of the near surface, while the copper layer of the copper clad aluminum conductor is about twice as thick as that.
For coaxial cable, because the transmission signal is above 5MHz, the transmission effect of copper clad aluminum conductor and pure copper conductor is the same.
The attenuation of the actual test cable proves this point.
Copper clad aluminum conductor is pure copper, in the process of production easier for straightening processing, thus to some extent, can say with copper clad aluminum cable than in pure copper conductor cable good return loss index.
Copper clad aluminum conductors are sold by weight, and pure copper conductors are sold by weight. Copper clad aluminum conductors are more expensive than pure copper conductors of the same weight.
But the same weight of copper clad aluminum is much longer than the pure copper conductor, and the cable is calculated by length.
The same weight, copper clad aluminum wire is 2.5 times the length of copper wire, and the price is only a few hundred yuan per ton.
Combined, copper clad aluminum has an advantage.
Because the copper clad aluminum cable is light, the transportation cost and installation cost of the cable will be reduced, which will bring some convenience to the construction.
Ii. Copper clad aluminum power cable.
Copper clad aluminum wire has a higher resistivity than pure copper wire, which is about 1.5 times that of pure copper wire. At the same time, the copper clad aluminum wire weighs about 1/2 of the pure copper wire.
According to the skin effect calculation, the resistivity of the copper conductor with the same cross section is equal to that of the copper conductor with the same cross section at the high frequency of 5MHz.
In use of 50 hz frequency of power cable, its copper conductor skin effect and proximity effect in above of 150 was gradually appears outstanding, at the same time due to the continuous development of science and technology, produce higher harmonic currents and energy will be injected into the power supply system, on the impedance of the system to produce corresponding frequencies of higher harmonic voltage, cause the distortion of the voltage waveform, increase the loss of the power supply system, increase the conductor heating;
In addition, the cable amplifies the harmonics, causing overvoltage at the junction and damaging the cable head.
The use of copper clad aluminum conductor can reduce the communication impedance (resistance) generated by high harmonics.
On other occasions, by raising the volume of copper in the copper clad aluminum monofilament and corresponding technological measures, make the copper clad aluminum/copper composite conductors in existing within the conductor diameter size limit, the same specification meet the requirements of conductor dc resistance.
Copper clad aluminum conductor can be used in the selection, design, use, installation and other aspects of the cable in the current years.
Reduce ac resistance.
Ac resistance is the main basis of current carrying capacity, according to the principle of skin effect, the surface of the solid conductor, the unit area by the current ratio of unit area of the center of the circle of the wire by the current, that is to say, the big cross section conductor's center in the conductor of the same circle area, circle smaller than the circumference of a circle by electric current, so the center conductor with the circular conductors with different metal composition is the most reasonable and economic.
Affect the ac resistance index except dc resistance and skin effect, and proximity effect, compared with the same dc resistance of the copper conductor, after using copper composite conductors, single conductors, at heart garden, aluminum bronze at the outer edge;
Within the stranded conductor, the inner layer is copper clad aluminum, the outer layer is pure copper, and aluminum skin effect and proximity effect to copper, copper composite conductor at the same time will increase the total cross section conductor part, therefore also increases the surface area of the conductor, and improve the cooling condition of the cable, increasing the cooling area, and the coefficient of thermal conductivity of aluminum and copper, under the condition of equal the cost of materials, the ac resistance index is much more economic.
Good corrosion resistance.
Aluminum is more susceptible to corrosion than copper, but due to the complete metallurgy of copper clad aluminum, aluminum is completely covered by copper and will not be exposed to water and air, which will achieve the same performance as copper.
Copper clad aluminum/copper composite conductors are also more conducive to avoid cable due to corrosion in the process of long-term use, bruising, or because of a bad press, tin welding conductor in contact with the terminals, fever caused by copper layer falls off and copper aluminum form electric potential difference between two kinds of metal, accelerated electrochemical corrosion, and cause the cable end fire hidden trouble.
For aluminum conductors, especially in the coastal areas, salt fog in the atmosphere of chloride ions will be condensed on the surface of aluminum, easy to cause local around the impurity and defects on the surface of the corrosion, holes, cracks and micro batteries, fuel corrosion of aluminum conductors.
Low cost and light weight.
Compared with the copper core cable of the same technical index, the copper clad aluminum conductor cable can save more than 40% of the cost, and the copper clad aluminum/copper composite conductor cable can save more than 20% of the cost.
The proportion of copper clad aluminum wire is only 37% to 40% of pure copper wire.
In the case of equal online diameter and weight, its length is 2.5 times that of pure copper wire.
Copper clad aluminum wire because of its surface is coated with pure copper, so it has the same weldability as pure copper wire, convenient for production.
Although copper clad aluminum cable has been born, and applied gradually, but there are no small resistance, mainly for copper clad aluminum cable it is difficult to find the country, the industry application basis, it is difficult to meet with the approval of design unit.
Copper clad aluminum cable there are quite a few products haven't the 3 c certification, the industry is still stays in the product identification, make enterprise standard stage, product specifications, features between different brand, using the standard difference is bigger, the engineering designer application is difficult to grasp, the investor is not willing to accept for the time being.
However, along with the national standards and regulations gradually improve and recognition, copper clad aluminum cable will be standardized, will undoubtedly be the highlight of the coming years wire and cable, lead to the development of the industry.
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