With the continuous development of the wire and cable industry, many coil products made of copper wire have appeared. The coil is used, and the coil gradually becomes darker after long-term use. The cable coil is black, even solar pv cables are no exception. Let's analyze the reasons for the black cable.

1. Technical reasons

Most businesses do not use oxygen-free copper. There is still oxygen in the copper. During the processing, the surface of the copper will inevitably be exposed to air and be oxidized. Due to the processing of the copper rod, especially the application of the toughening process, and the poor storage conditions of the finished copper wire core, the copper wire itself will still be slightly oxidized.

2. The material problem of the insulating layer

Insulating paint can be divided into five categories: impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint, and anti-corona paint. Among them, the impregnating varnish is used to impregnate the coils of motors and appliances. The impregnating varnish can fill the gaps and micropores of the insulation system, and form a continuous paint film on the surface of the impregnated material so that the coil is bonded into a solid whole, which effectively improves the integrity, thermal conductivity, and moisture resistance of the insulation system and the dielectric strength. And mechanical strength. Secondly, it also plays a role in heat dissipation. After the insulating varnish is soaked, the dried coil can be regarded as a whole, and the heat of the inner and outer layers can be easily conducted to dissipate heat.

3. Usage issues

In the process of using the copper wire of the coil, we often encounter such problems: collision, friction, slow washing speed, and a large amount of water contacting the coil; using waste engine oil to lubricate, resulting in residual conductor surface and damage to the insulation layer; conductor in subsequent processing Oxidized.