Power cord copper, aluminum monofilament drawing
The copper and aluminum rods commonly used in power cords are used to pass through one or several die holes of a drawing die at room temperature to reduce the cross-section, increase the length and improve the strength. Drawing is the first process of each wire and cable company, and the main process parameter of drawing is the mold matching technology.
Power cord monofilament annealing
When the copper and aluminum monofilaments are heated to a certain temperature, the toughness of the monofilament is improved and the strength of the monofilament is reduced by the method of recrystallization, so as to meet the requirements of the wire and cable for the conductive core. The key to the annealing process is to eliminate the oxidation of the copper wire.
Stranding of the conductors of the power cord In order to improve the flexibility of the power cord and facilitate the laying of the device, the conductive core is formed by twisting a plurality of monofilaments. From the twisting method of the conductive wire core, it can be divided into regular twisting and irregular twisting. Non-regular stranding is further divided into bundle stranding, concentric compound stranding, and extraordinary stranding. In order to reduce the occupied area of the wire and reduce the geometric size of the power line, the stranded conductor is also compressed, so that the ordinary round
The shape changes into a semicircle, fan shape, tile shape, and compact circle. This type of conductor is primarily used on power lines.
Power cord insulation extrusion Plastic power cord mainly adopts extruded solid insulation layer, the main technical requirements of plastic insulation extrusion:
1. Eccentricity: The deviation value of the extruded insulation thickness is the main indicator of the degree of extrusion workmanship. Most of the product structure dimensions and their deviation values have clear rules in the specification.
2. Lubricity: The surface of the extruded insulating layer needs to be lubricated, and there should be no poor quality problems such as rough appearance, scorching, and impurities.
3. Density: The cross-section of the extruded insulating layer should be dense and strong, with no pinholes visible to the naked eye, and no bubbles.
power cord
For multi-core power cords, in order to ensure the formability and reduce the shape of the power cord, it is generally necessary to twist them into a circular shape. The mechanism of twisting is similar to that of conductor twisting, because the twisting pitch is larger, and most of them adopt the method of no back-twisting. Technical requirements for cabling: First, the twisting of the cable is caused by the twisting of the insulated wire core; the second is to prevent the insulating layer from being scratched.
Most of the cables are also completed with two other processes during the cable formation: one is filling, which ensures the roundness and stability of the cable after the cable is formed; the other is bundling, which ensures that the cable core is not loose.
Power cord inner sheath
In order to protect the insulated core from being damaged by the armor, it is necessary to properly protect the insulating layer. The inner sheath is divided into the extruded inner sheath (isolation jacket) and wrapped inner sheath (cushion layer). The replacement of the binding tape by the wrapping cushion is carried out simultaneously with the cabling process.
Power cord armor
Laying in the underground power line, it can accept the certain positive pressure effect during the task, and the inner steel tape armored structure can be selected. The power cord is laid in a place with both positive pressure effect and tension effect (such as water, vertical shaft, or soil with large drop).
Power cord outer sheath
The outer sheath is a structural part that protects the insulation layer of the power cord from corrosion of environmental elements. The main effect of the outer sheath is to improve the mechanical strength of the power cord, resist chemical corrosion, moisture, and water immersion, and prevent the power cord from burning.
