For the electromechanical installation industry, wire and cable occupy an important position in the electromechanical installation engineering. As the main raw material, copper accounts for 70%~80% of the total cost of cable products. The price of copper cables increases sharply with the increase of copper prices. Investors and construction parties have brought great difficulties in project cost control. For this reason, the research and application of copper-clad aluminum cables has grown rapidly.
The copper-clad aluminum cable refers to a wire and cable in which an aluminum core wire is used instead of copper to form a cable main body, and a copper layer of a certain proportion is externally baked. Copper-clad aluminum cables can be divided into two categories according to their applications: one is copper-clad aluminum cable for signal or communication purposes, and the other is copper-clad aluminum cable for power supply. For its characteristics, copper-clad aluminum and pure copper cables were compared as follows.
1. Copper-clad aluminum communication cable
Mechanical properties. The strength and elongation of pure copper conductors are larger than that of copper-clad aluminum conductors, which means that pure copper is better in mechanical properties than copper-clad aluminum. From the point of view of cable design, the advantage of pure copper conductors being better than that of copper-clad aluminum conductors is not necessarily required in practical applications. Copper-clad aluminum conductors are much lighter than pure copper, so copper-clad aluminum cables are lighter in overall weight than pure copper conductor cables, which will facilitate cable transportation and cable rackwork. In addition, copper-clad aluminum is softer than pure copper, and cables made of copper-clad aluminum conductors are better in softness than pure copper cables.
Electrical performance. Because the conductivity of aluminum is worse than that of copper, the DC resistance of the copper-clad aluminum conductor is larger than that of the pure copper conductor. Does this affect whether the cable will be used for power supply, such as supplying power to the amplifier, if it is used for power supply? Copper-clad aluminum conductors will result in additional power consumption and a lower voltage drop. When the frequency exceeds 5 MHz, the AC resistance attenuation at this time is not significantly different between the two different conductors. Of course, this is mainly due to the skin effect of high-frequency current. The higher the frequency, the closer the current flows to the surface of the conductor. The surface of the copper-clad aluminum conductor is actually pure copper. When the frequency is high, the whole current is plated. Flowed inside the copper material. At 5 MHz, the current flows in a thickness of about 0.025 mm near the surface, while the copper layer of the copper clad aluminum conductor is about twice as thick as this thickness. For the coaxial cable, since the transmitted signal is above 5 MHz, the copper-clad aluminum conductor and the pure copper conductor have the same transmission effect. The attenuation of the actual test cable can prove this. Copper-clad aluminum is softer than pure copper conductors, and is easily straightened during the production process. Therefore, it can be said that copper-clad aluminum cables are better than cables with pure copper conductors.
Economical. Copper clad aluminum conductors are sold by weight, pure copper conductors are also sold by weight, and copper clad aluminum conductors are more expensive than the same weight of pure copper conductors. 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 the copper wire, the price is only a few hundred dollars per ton. Combined, copper clad aluminum has an advantage. Since the copper-clad aluminum cable is relatively light, the transportation cost and installation cost of the cable will be reduced, which will bring certain convenience to the construction.
Second, copper clad aluminum power cable
DC resistivity. The resistivity of the copper clad aluminum wire is larger than that of the pure copper wire, which is about 1.5 times that of the pure copper wire. When the negative value is the same, the weight of the copper clad aluminum wire is about 1/2 of that of the pure copper wire. According to the calculation of the skin effect, the electrical resistivity is equal to that of the copper conductor of the same cross section at a high frequency of 5 MHz or more. In the use of power cables with a frequency of 50 Hz, the skin effect and proximity effect of the copper conductors are gradually prominent above 150 mm2. At the same time, due to the continuous development of science and technology, high-order harmonic currents and energy are injected into the power supply system. Producing a higher-order harmonic voltage of the corresponding frequency on the impedance of the system, causing the waveform of the voltage to be distorted, increasing the loss of the power supply system, and increasing the heat generation of the conductor; in addition, the cable amplifies the harmonics and generates an overvoltage at the joint. Damage to the cable head. The use of copper-clad aluminum conductors serves to reduce the AC impedance (resistance) generated by higher harmonics. In other applications, by increasing the volume of copper in the copper-clad aluminum monofilament and the corresponding technological measures, the copper-clad aluminum/copper composite conductor meets the DC resistance requirements of the conductor within the upper limit of the outer diameter of the existing conductor of the same specification.
Connection method. The copper-clad aluminum conductor can meet the habits of product selection, design, use and installation of the wire and cable that have been to be continued for many years, and it is also advantageous for the cable terminal crimping and tin welding.
Reduce the AC resistance. The AC resistance is the main basis of the current carrying capacity. According to the principle of the skin effect, the surface of a single wire passes through a current larger than the current per unit area of ​​the wire, that is, the center of the large-section conductor. In the circular area where the same conductor is formed, the center of the circle is smaller than the current passing through the circumference, so it is most reasonable and economical to combine the center conductor and the circumference conductor with different metals. In addition to DC resistance and skin effect, there are adjacent effects. Compared with copper conductors with the same DC resistance, copper composite conductors are used. In a single conductor, aluminum is in the center of the circle and copper is on the outer edge. In the conductor, the inner layer is copper-clad aluminum, the outer layer is pure copper, and aluminum is not sensitive to copper for skin effect and proximity effect, and the copper composite conductor increases the total cross-section of the conductor, thus increasing the conductor. The surface area improves the heat dissipation condition of the cable and increases the heat dissipation area. The thermal conductivity of aluminum is similar to that of copper. Under the same material cost, the index of AC resistance is much more economical.
Good corrosion resistance: Aluminum is more corrosive than copper. However, since the copper clad aluminum material has been completely metallized, the aluminum is completely covered by copper and will not be contacted by water or air, and fully achieve the same performance as copper. The copper-clad aluminum/copper composite conductor is also used to avoid the corrosion of the cable during long-term use due to corrosion, bumping or due to tightness, poor soldering, poor contact between the conductor and the terminal, heat generation caused by copper layer peeling and copper and aluminum. A potential difference is formed between the metals to accelerate the galvanic corrosion, causing a hidden danger of burning the end of the cable. For aluminum conductors, especially in coastal areas, the chloride ions contained in the salt mist in the atmosphere will condense on the surface of aluminum, causing local corrosion around the surface impurities and defects, forming holes, cracks and micro-cells, exacerbating the aluminum conductor. corrosion.
Low cost and light weight. Compared with copper core cables of the same technical specifications, copper clad aluminum conductor cables can save more than 40% of cost, and copper clad aluminum/copper composite conductor cables can save more than 20% of cost. The proportion of copper clad aluminum wire is only 37%-40% of pure copper wire. When the wire diameter and weight are equal, the length is 2.5 times that of the pure copper wire.
Good weldability. Since the copper clad aluminum wire is covered with a layer of pure copper concentrically, it has the same solderability as the pure copper wire and is convenient for production.
Although copper-clad aluminum cable has been born and is gradually being applied, there is still no small resistance. The main performance is that copper-clad aluminum cable is still difficult to find the application basis of the country and industry, and it is difficult to get recognition from the design unit. There are still quite a few products in the copper-clad aluminum cable, and there is still no 3C certification. The industry is still at the stage of product identification and setting of enterprise standards. The product specifications, characteristics and usage standards of different brands are quite different, and it is difficult for engineering designers to apply. Grasp, the investor is not willing to accept it for the time being.
However, with the gradual improvement and recognition of national standards and regulations, copper-clad aluminum cables will surely become standardized, which will undoubtedly become the highlight of wire and cable in the next few years, driving the development of the entire industry.
Concerned about surprises
Label: Characteristics and application of copper clad aluminum cable
Previous: The difference between power cable and control cable Next: Winter leather sofa to "replenish water"
Ultra-high pressure (UHP) water jetting equipment is engineered by diesel engine with Ultra High Pressure water to cleaning the surface according to
clients need .4mm thickness stainless steel tank and double water filter system helps extend water jetting equipment running life.
Available with a skid or trailer unit, Botuo diesel UHP water jetting equipment offer a host of features to provide contractors with enhanced
performance, superior durability.
BOTUO UHP water jetting equipment deliver a host of engineered improvements. One of the most notable changes is the integrated design of the whole of the water jet unit to save the place it extend system life and keeps the high pressure seals of the pump as well .
All operating system, including the pressure adjusted valve and pressure gauge with snubber, are mounted on a separate accessory manifold, which
provides additional protection for these important components of the pump .
Powerful performance and undeniable reliability are just two reasons of Botuo UHP water blasting system is the clear choice for your industry cleaning
applications.
With operating pressures from 800bar to 3000 bar, it is ideally suited for a wide variety of cleaning in the chemical and ship hull industry for rust and
paint cleaning .
HP sealing made by super composite material enables high durability of the high pressure seals and counteracts the ingress of air.
Application:
Dock cleaning
deck cleaning
water rust removal
Heat Exchanger Cleaning
Condenser cleaning
Boiler cleaning
Chimney Cleaning
aircraft carrier cleaning
High-speed rail cleaning
road sign removal
leaning & Refurbishing Ocean-Going Vessels
Scaffold cleaning
ship maintenance, water rust removal, sad blasting, dock cleaning, ultra-high pressure testing
Zhejiang Botuolini Machinery Co.,Ltd , https://www.chinaplungerpump.com