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Wire and cable wear resistance includes two aspects: a) the ability of the sheath to withstand abrasion; b) The ability of the cable marking to resist wear. purpose: The purpose of this test is to determine the ability of the cable jacket to withstand wear. Sample: The specimen shall be a length of cable sufficient to carry out the specified test and is typically 750 mm in length. Wire and cable wear resistance testing machine: The wire and cable sheath abrasion tester shall be capable of rubbing the surface of the cable back and forth in a direction parallel to the longitudinal axis of the cable at a frequency of (5 ± 5) cycles per minute over a length of (10 ± 1) mm. The rubbing edge moves back and forth once to form a loop.   The wiping edge shall be a steel needle whose diameter is to comply with the specifications in the detailed specification. Wire and cable wear tester test steps: 1. Fasten the specimen with a length of approximately 750 mm to the support plate with a cable clamp. Then, the weight should be loaded on the wiping edge to produce the force stated in the detailed specification on the cable, while avoiding collision with the cable. 2. Unless otherwise specified in the detailed specification, perform 4 tests on each sample, move the sample forward 100 mm before the next test, and always rotate the 90° angle in the same direction.   Test requirements: After the specified number of cycles has been completed, the sheath shall be free of perforations and the fiber shall maintain optical continuity.   To be specified: The detailed specification should include the following: a) the number of cycles; b) needle rod diameter; c) the force applied.

1. Stretching of wire The stretching of the wire refers to a pressure processing method in which the wire blank is plastically deformed by the die hole under a certain tensile force to reduce the section and increase the length. 2. Characteristics of stretching (1) The stretched wire has a relatively precise size, the surface is smooth, and the cross-sectional shape can be varied. (2) It can stretch wires of large length and various diameters. (3) Mainly in cold processing, the drawing process, mold and equipment are simple, and the production efficiency is high. (4) The tensile energy consumption is large and the deformation is limited.   3. The principle of stretching Stretching is a range of pressure processing. In addition to producing very little dust, the volume changes little during the stretching process, so the volume of the metal before and after stretching is substantially equal. 4. Factors affecting stretching (1) Copper and aluminum rod (wire) materials. When the other conditions are the same, the tensile strength of the drawn copper wire is larger than that of the drawn aluminum wire, and the drawn aluminum wire is easily broken, so a larger safety factor should be taken when pulling the aluminum wire. (2) The tensile strength of the material. There are many factors for the tensile strength of materials, such as the chemical composition of the material, the calendering process, etc., and the tensile strength is high when the tensile strength is high. (3) Degree of deformation. The greater the degree of deformation, the longer the length of the deformation section of the die hole, thus increasing the positive pressure of the die hole against the wire, the frictional force also increases, and the tensile force also increases. (4) The coefficient of friction between the wire and the die hole. The greater the coefficient of friction, the greater the tensile force. The coefficient of friction is determined by the finish of the wire and mold material, the composition and quantity of the lubricant. (5) The size and shape of the working area and sizing area of the wire die hole. The larger the sizing zone, the greater the tensile force. (6) The position of the wire mold. Improper placement of the wire mold or skewing of the mold base also increases the tensile force. Also the wire diameter and surface quality are not up to standard. (7) External factors. The wire is not straight, the jitter of the wire in the process of pulling the wire, and the resistance of the wire release will increase the tensile force.

Everyone knows that cable water is a very serious problem. Sometimes you think you have done a good waterproofing, but the cable is still in the water. So how does the cable get into the water? Let me introduce to you the reasons and countermeasures for cable water intake.   1. At the time of storage: the newly purchased power cable is sealed with plastic sealing sleeves at both ends, but after a period of use, the rest is wrapped with plastic paper, and the outside is tied with a rope. The sealing is not good, and the days are long. Water vapor will seep into the cable. 2. When the cable is laid: When the cable is laid, the cable head wrapped with plastic paper is sometimes immersed in water to make the water enter the cable; when the cable is pulled and piped, the outer sheath rupture sometimes occurs. 3. After laying: The cable head is not produced in time, so that the unsealed cable port is exposed to the air for a long time, even immersed in water, so that the water vapor enters the cable in large quantities.     Now that I know the reason for the water in the cable, is there any rescue measures? At present, as far as I know, there is no remedy, it can only be prevented. There are several small suggestions and methods to prevent and reduce cable water intake.   1. The cable head should be sealed. The cable ends that are sawn off, whether stacked or laid, must be sealed with a special cable to prevent moisture infiltration. 2. The cable head should be produced in time after the wire is laid. Strengthening the management of the cable head manufacturing process Once the cable enters the water, the earliest breakdown phenomenon is often the cable head, so the wire head is made well and the overall life of the cable can be extended. 3. The long cable adopts several long cables of cable branch box, each of which is about 3,000 meters long. For such a cable, in addition to the intermediate joint, one or two cable branch boxes are used, once one of the cables enters the water. , does not spread to other sections of the cable.

When a breakpoint occurs inside the cable or cable, it is difficult to visually determine the determined position of the breakpoint due to the wrapping of the outer insulation. Here are a few ways to quickly determine the breakpoints of wires and cables: Non-damaged cable method 1. digital multimeter method First, connect one end of the cable with the breakpoint to the 220V live wire and the other end to make it float. Move the multimeter's gear position to make it to the AC 2V voltage block. Then, starting from the Firewire access terminal of the faulty cable, hold the black test lead with one hand and the red test lead slides slowly along the insulation of the faulty cable. The voltage at the no break point of the cable is about 0.445V. When the red test pen moves to a certain place, the voltage value displayed by the multimeter drops to 1/10 of the normal voltage, that is, 0.04V. At this point, it can be basically concluded that the breakpoint is at the position forward (fire line access end) 15cm. This method cannot be used if the shield of the shielded wire is not damaged.     2. induction pen method First, remove the cable around the breakpoint cable and connect the cable with the breakpoint to the live wire. Then use the induction pen to move slowly perpendicular to the cable. When the AC signal of the induction pen disappears, you can judge the breakpoint at the test. At the point, the error is no more than 10cm.     3. Polyline method For short cable test breakpoints, you can use the method of bending, and connect the two ends of the cable to the ends of the red and black test leads of the multimeter. Bend back and forth from one end of the cable. If the multimeter is on and off at this time, the breakpoint is here. According to this method, the breakpoint is always checked.   Method of damaging the cable 4. acupuncture discrimination This method uses the continuity of the cable to check the breakpoint of the cable. Insert the segment of the breakpoint cable into the steel pin, and then use a multimeter to measure the on-off condition. The difference is where the breakpoint is. However, this method destroys the insulating layer and is easily caused by other problems in the later use of the cable.   5. professional instrument detection method In addition, for the judgment of the underground cable fault point, the fault point can be judged by the audio detector.   For the cable length and the judgment of the short circuit and the breaking point, a cable fault telemeter can be used.     Different methods are used to judge the breakpoint according to the actual situation. The above several methods can basically determine the cable breakpoint.