Classification and basic characteristics of the ho

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Classification and basic characteristics of wires and cables

classification and basic characteristics of wires and cables - Heming cable let's learn about the classification of wires and cables (Heming)

wires and cables are defined as wire products used to transmit electric (magnetic) energy, information and realize electromagnetic energy conversion. Wires and cables in a broad sense are also referred to as cables. Chivalrous cable refers to insulated cable. It can be defined as: an aggregate composed of one or more insulated cores, as well as their respective possible cladding, general protective layer and outer protective layer. Cables may also have additional uninsulated conductors

in order to facilitate the selection and improve the adaptability of products, China's wire and cable products are divided into the following five categories according to their uses

1) bare wires refer to products with only conductors but no insulation layer, including copper, aluminum and other metals and composite metal round single wires, stranded wires, flexible wiring, wire types and profiles for overhead transmission lines of various structures

2) winding wire

cut the magnetic line of force in the magnetic field in the form of winding to induce current, or generate a magnetic field through current. According to the wire used by Bloomberg 24 last month, it is also called electromagnetic wire. Including enameled wire, wrapped wire, inorganic insulated wire, etc. with various characteristics

3) power cable

cable products used to transmit and distribute high-power electric energy in the main line of the power system, including power cables with various voltage levels of 1~330kv and above and various insulation

4) communication cables and optical cables

communication cables are cables for transmission, telegraph, television, broadcasting, fax, data and other telecommunication information, including urban communication cables, long-distance symmetrical cables and coaxial (trunk) communication cables, with transmission frequency of audio ~ tens of MHz

communication optical cable uses optical fiber (optical fiber) as the optical wave transmission medium for information transmission, so it is also called fiber optical cable. The elongation value automatically shows that the transmission attenuation is small, the frequency band is wide, the weight is light, the outer diameter is small, and it is not disturbed by electromagnetic fields. Therefore, the communication optical cable has gradually replaced 3 There is contact between the toothed bar pressing plate and the toothed bar, which replaces the communication cable. According to the optical fiber transmission mode, there are single-mode and multi-mode. According to the structure of optical cable, there are many forms, such as layer stranding type, skeleton type, central tube type, layer stranding unit type, skeleton unit type and so on. According to their different use environments, optical cables can be divided into direct buried optical cables, pipeline optical cables, overhead optical cables, underwater or submarine optical cables and other forms

compared with communication cables, radio frequency cable type is suitable for cables that transmit radio frequency (radio) signals in radio communication, broadcasting and related electronic equipment, also known as radio cables. Its use frequency ranges from a few megahertz to tens of megahertz, which is the radio frequency range of high frequency, very high frequency (VHF) and ultra high frequency (UHF). The vast majority of RF cables adopt coaxial structure, and sometimes adopt pair forming and strip forming results. It also includes waveguide, dielectric waveguide and surface wave transmission line

5) wires and cables for electrical equipment

wires and cables for power connection lines that can directly transmit points from the distribution point of the power system to various electrical equipment and appliances, and wires and cables for electrical installation lines and control signals in various industrial and agricultural equipment belong to this category of products. This kind of product is the most widely used and has the most varieties, and most of them need to determine the structure and performance of the product in combination with the characteristics of the equipment used and the operating environmental conditions. Therefore, in addition to a large number of general products, there are many special and special products

basic characteristics of wires and cables (Heming)

the most basic performance of wires and cables is to effectively transmit electromagnetic waves (fields). In essence, wire and cable is a guided wave transmission line. Electromagnetic waves are guided and propagated in the cable according to the regulations, and the conversion of electromagnetic field energy is realized in the process of propagation along the line

generally, the loss of electromagnetic wave propagating in insulating medium is small, while the part of electromagnetic wave propagating in metal is often lost into heat due to imperfect conductor. The characteristic parameters that characterize the transmission of electromagnetic waves along the cable loop are called transmission parameters, which are usually expressed by two parameters, the propagation constant in the complex form and the characteristic impedance

Another key basic feature of

cable is its adaptability to the use environment. Different use environments have corresponding requirements for the performance of wires and cables, such as high temperature resistance, low temperature resistance, corona resistance, irradiation resistance, air pressure resistance, water pressure resistance, oil resistance, ozone resistance, atmospheric environment resistance, vibration resistance, solvent resistance, wear resistance, bending resistance, torsion resistance, tension resistance, compression resistance, fire resistance, lightning protection and biological invasion resistance. In the standards and technical requirements of cables, very specific test or test methods should be put forward for environmental requirements, so as to put forward very specific test or test methods for environmental requirements, as well as corresponding assessment indicators and inspection methods. For some cables working under special service conditions, their applicability should be assessed according to the additional service requirements to ensure the integrity and reliability of the cable engineering system

because wire and cable products are used in different occasions, the performance requirements are multifaceted and very extensive. On the whole, its main performance can be summarized as follows:

1) electrical performance

conductivity most products require good conductivity, and individual products require a certain resistance range

electrical insulation performance avoid the damage of insulation resistance, dielectric constant, dielectric loss, voltage withstand characteristics, etc. of extensometer due to human overload

transmission characteristics refer to high-frequency transmission characteristics, anti-interference characteristics, etc

2) mechanical properties

refer to tensile strength, elongation, bending, elasticity, softness, vibration resistance, wear resistance, impact resistance, etc

3) thermal performance

refers to the product's heat resistance grade, working temperature, heating and heat dissipation characteristics of power cables, current carrying capacity, short circuit and overload capacity, thermal deformation and heat shock resistance of synthetic materials, expansion of materials, dripping performance of impregnation or coating materials, etc

4) corrosion resistance and post riding performance

refers to electrochemical corrosion resistance, biological and bacterial corrosion resistance, chemical drugs (oil, acid, alkali, chemical solvents, etc.) corrosion resistance, salt fog resistance, sunlight resistance, cold resistance, mold resistance and moisture resistance

5) aging performance

refers to the ability of products and their constituent materials to maintain their original performance under the action of mechanical (stress) stress, electrical stress, thermal stress, and other external factors, or under external climatic conditions

6) other properties

include the physics of some materials (such as the hardness and creep of metal materials, the compatibility of polymer materials) and some special use characteristics of products (such as flame retardancy, atomic radiation resistance, insect bite prevention, delayed transmission, energy damping, etc.)

the performance requirements of products are mainly put forward from the use, service conditions and supporting equipment relationship of each specific product

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