guangxi cable news: how to identify the video line
from：guichao author：admin click： 324 addtime：2017-04-14 13:34:08
visual appearance identification:
1:pvc sheath: the surface can be seen inside the network compression of the regular "roughness"",
it shows that the processing technology is good, it will not produce relative sliding. smooth appearance,
can not see the compression of the network of "roughness", with the hand pinch jacket is loose dynamic, is poor cable;
2: check the shielding layer network: the number is enough? copper wire mesh, check solderability,
tinned copper wire scraping is not inside the copper wire, aluminum magnesium alloy wire hardness is significantly greater than the copper wire;
the network is sparse, the distribution is not uniform, and the insulation layer is not tight, etc.;
3: check the core line: diameter - syv cable is 0.78-0.8mm,
sywv cable is 1.0mm; a 1.0mm cable with a diameter of syv75-5 has been developed recently,
the characteristic impedance of the cable is certainly not 75 ohms and is not applied to a 75 ohm transmission system;
4: check the bonding force between the core and the insulation layer: inclined to cut the insulation layer, according to the direction of the peel off the core line,
see the core line and the insulation layer has no bonding process materials; good cable has a greater adhesion, the difference between the cable does not stick;
5: longitudinal tensile test: take one meter cable, delamination peeling core line, insulation layer, shielding layer, the outer cover,
each stay 10 cm long. the method is that two hands are respectively holding two adjacent layers of the cable to pull in the opposite direction;
the general strength of the cable is not pulled, the cable can not be easily pulled out,
elevator cable is very important, many of the so-called elevator cable are the existence of this problem.