Shielded cables in moving applications

Jan Arnoldy | 9. April 2020

In some articles we have already mentioned how important the appropriate shielding is for the cable. Today we would like to take a closer look at this component of the cable, especially shielded cables in moving applications.

In the process we would also like to answer the following questions:

Why does a cable need a shield? And what do we have to look out for in terms of shielding?

Why are shielded cables used?

The shield of a cable serves as electromagnetic compatibility protection. It prevents interfering signals from the inside of the cable from reaching the outside and disturbing other cables or even electrical devices. Furthermore, the shield serves to ensure that external interference does not reach the inside of the cable.

What is meant by electromagnetic compatibility protection?

EMC stands for electromagnetic compatibility and describes that different devices do not influence each other. To ensure this protection, a cable must be electrically shielded. This protective effect is expressed strongly by the indication of the optical coverage of the shield. This is the area of the cable that is optically covered by the shield.

For example, if the cable has a foil as its shield, it can be said to have 100% coverage. The optical coverage of our chainflex cables can reach a value of max. 90% due to a shield consisting of tinned copper wires.

What do you have to pay attention when using a shield?

Too acute braid angles of the shield or the sole use of foil shielding can often lead to error patterns such as shield breakage. To ensure that these faults no longer occur, our shielded chainflex cables use either braided or wrapped shielding, depending on the type of application.

Important for the appropriate shielding for linear applications is a braided shield with a particularly flat braid angle. The electromagnetic compatibility protection is consistently good during movement, because the shielding window opens only minimally in the radius.

Differences in linear and torsional application

The cable shielding should always be selected according to the type of application. With our chainflex cables we distinguish between cables for linear applications in an e-chain and torsional applications such as on robots.

For a linear movement you should not use the same shield as for a torsion movement, but a braiding as described above.

Cable with braided shield
Braided shield

For cables used in torsion applications, we use a shield wrap if possible. Here the copper wires of the shield are not braided, but wrapped in one direction. Optically, this is comparable to a spiral that wraps itself around the inner part of the cable.

Cable with shield wrap
Cable with shield wrap

In this way a high shield coverage can also be ensured in a torsion application, as the shield can open and close in motion.

Find the right cable for your application from our range. We are happy to assist and advise you so that you too can find the right cable for your application.

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