LAN cables are essential in power systems, especially in power lines, and there are several categories, such as special cables, insulated cables, and so on.
copper conductor cable is used to transmit electrical (magnetic) energy, information and electromagnetic energy conversion of wire products, broad wire and cable is also referred to as cable, narrow cable refers to insulated cable.
Defined as an aggregate consisting of the following parts; One or more insulated wire cores, and the cladding, total protective layer and outer protective layer they may each have, and the cable may have additional uninsulated conductors.
1.check the shielding layer mesh: whether the number of braiding is enough copper mesh, check the weldability, tinned copper computer wire scraping to see whether the inside is copper wire, aluminum magnesium alloy wire hardness is significantly greater than copper wire; The network is sparse, the distribution is not uniform, and the insulation layer is not tightly wrapped. Burn the core wire with a lighter, if it is copper-clad aluminum, it is easy to see that the internal color is not the same as the copper outside; Peel off the skin, look at the shielding layer knitting Angle, if basically stand up, then basically you can see that the knitting Angle is large, for jerry-cutting products.
2.PVC sheath: the surface can be seen to press the inside of the regular "uneven", indicating that the processing technology is good, will not produce relative sliding, is a good cable. The appearance is smooth, can not see the "unevenness" of the compacting mesh, and the sheath is loose when pinched by hand, which is a poor cable.
3.check the adhesion force of copper core wire and insulation layer: cut the insulation layer diagonally, pull the core wire in the peeling direction, and see whether the core wire and insulation layer are adhered to process materials; Good cable has a larger adhesion force, poor cable has no adhesion.
4.check the core wire: diameter -- SYV cable is 0.78-0.8mm, SYWV cable is 1.0mm; Recently, there has been a SYV75-5 cable with a core diameter of 1.0mm, and the characteristic impedance of this cable is definitely not 75 ohms, and it is not used in 75 ohms transmission systems. Check the diameter of the inner core of the cable with a vernier caliper.
5. longitudinal tensile test: take one meter security alarm wire, stratified strip the core wire, insulation layer, shielding layer, outer cover, each leave 10 cm long. The method is: two hands respectively hold the adjacent two layers of the cable, pull in the opposite direction; Good cables generally can not be pulled by force, and the difference cable can be easily pulled out without great effort.
6. open a roll of wire to measure the length, or use the method of weighing to roughly judge.
Post time: 2024-01-25 11:25:04