Cores wound in bundles and cores wound in layers

What is cores wound in bundles?

Cores wound in bundles is defined by its very complex internal structure. Three, four or five cores are stranded together to form a bundle. These individual bundles are then stranded together again in the opposite direction around a high tensile strength centre element. The result is called a total stranding.

Advantages

The advantage of cores wound in bundles is that the push and pull forces on the cores in the cable are better distributed, as the cores change position very quickly within the cable. As a result, the push and pull forces are equalised and the stranding remains strong even if the cable is subjected to high bending stress. This specification makes them ideally suited for use in e-chains.

Disadvantages

Not all cable types have enough cores to be manufactured in a cores wound in bundles version. It is generally more difficult and more cost-intensive to produce a cable with its cores wound in bundles.

What is cores wound in layers?

In cores wound in layers, the cable cores are stranded more or less tightly and usually relatively long in several layers around a centre and provided with a jacket extruded onto a hose. This stranding is suitable for cables with up to seven cores. For shielded cables, the cores are also wrapped with fleece or foil.

Advantages

Cores wound in layers is usually easier to manufacture and has lower costs.

Disadvantages

Low costs are very tempting at first glance. However, with more than seven cores, this can quickly turn out to be an expensive mistake.

In a bending process, the core in the inner radius is compressed during the movement. At the same time, the core in the outer radius is stretched. This behaviour causes the cores inside the cable to shift. In the long term, the shifting of the cores can lead to broken cores and the so-called corkscrew effect of the cable.