The main function of cable armour and stranding
Armored cable refers to cable with metal armored protective layer. The purpose of cable armored layer is not only to enhance the mechanical protection such as tensile strength and compressive strength to extend the service life, but also to improve the anti-interference performance of cable through shielding protection.
Common armor materials include steel tape, steel wire, aluminum tape, aluminum tube, etc., among which steel tape and steel wire armor layer has high magnetic permeability and good magnetic shielding effect, which can be used to resist low-frequency interference, and can make the armored cable buried directly without pipe penetration. Moreover, it is cheap and good in practical application.
Different specifications and different number of copper wire according to certain order and lay twisted together, became the conductor of larger diameter, large diameter of this kind of twisted after stranded conductor than single copper wire of the same diameter size is more soft, made of wire bending performance is good, the swing test is not easy to break, when for some of soft wire of the request (for example medical grade wire) is more easy to meet the requirements.
From the electrical performance: the conductor current, due to the resistance consumption of electricity and heat. As the temperature rises, the performance life of insulating layer and protective layer material will be affected. In order to make the cable run efficiently, the conductor section should be enlarged. However, the single conductor with large section is not easy to bend and has poor softness, which is not conducive to production, transportation, installation and laying. From the mechanical properties and requirements of softness, reliability, multiple single twisted twisted together, can solve the contradiction.