No Chance for Interference Currents: LAPP as an EMC Technology Partner

Original Content Written By: LAPP

Avoid interference from electromagnetic fields in industrial applications with shielded cables, cable glands, and connectors from LAPP.

In the smart factory, high electrical power and an increasing amount of data are transferred in a tight space. This increases the risk of electromagnetic interference – even one poorly screened connector can paralyse an entire production process. So it's no wonder that the industry for electromagnetically compatible solutions is on the rise – currently at seven percent per year worldwide. Optimum electromagnetic compatibility (EMC for short) requires a good understanding of the system and the selection of the right components. Users get both from LAPP.

Read the EMC whitepaper, where LAPP experts answer the most important questions on the topic of EMC: EMC Problems in Production and How to Avoid Them.

How does EMC work?

An electromagnetic interference always originates from an interference source. This can be an item of equipment that carries a high current, such as a frequency controlled motor or a cable.

The source of interference corresponds to a disrupted piece of equipment, known as the interference sink. The interference sink can be a sensor or data network cable, for example.

The coupling mechanism in between causes the interference. This can be divided into four different types of coupling:

In practice, this is usually a mixture of these 4 coupling mechanisms, which must be eliminated, for example by using screened cables.

EMC check with the LAPP Health Check Service

What is the EMC directive?

In EMC Directive 2014/30/EU, Article 3, electromagnetic compatibility is defined as:

"[...] the ability of a piece of equipment to operate satisfactorily in its electromagnetic environment without causing electromagnetic interference, which would be unacceptable for other equipment in this environment."

According to this definition, EMC has two main aspects:

How to Ensure Good EMC

How are screened power and control cables constructed?

There are four different screening types for power and control cables. Three of these shields are particularly suited to use with EMC protection:

How are screened data cables constructed?

Data cables have essentially the same screening as power and control cables, but other abbreviations are common in product designations:

There are also two special features for data cables in terms of their screening rating for EMC protection:

Unscreened

Data transmissions are particularly susceptible to interference, which is why data cables are generally always screened. For certain areas of application for signal transmission, there are unscreened data cables specially marked with the abbreviation “U” (unscreened), such as the Cat.6 network cable ETHERLINE® LAN Cat.6 U/UTP 4x2xAWG24 LSZH, the Cat.5e Ethernet cable ETHERLINE® LAN Cat.5e SF/UTP 4x2xAWG24 or our UNITRONIC® BUS ASI cables for networking systems in the field.

Why are connectors important for EMC protection?

Every system is only as good as its weakest point. LAPP connector systems have the advantage of using all the aforementioned screening connection concepts. Very often, EMC cable glands are already integrated into the connector, offer the option of connecting a protective hose and enable the cable screening to be contacted with the working or PE contact of the connector system.

The standard housing is powder-coated with a non-conductive seal between the housing parts, which insulates them from one another. EPIC® EMC connectors offer 360-degree screening and vibration-proof screening connection. The EMC connectors can be identified by their metallically conductive, usually nickel-plated surface. The seals are designed to ensure that the two housing parts pressed or screwed together are in low-resistance contact with metal on metal. The same principle applies to both cable glands and the mounting wall.

Rectangular connectors feature an integrated SKINTOP® MS-M BRUSH cable gland. EPIC® ULTRA H-A3 and EPIC® ULTRA H-B6-24 are therefore easy to assemble and designed for a wide cable clamping range in screened cables.

If you need a space-saving design, for example for use in servo drives, actuators and sensors, we recommend the POWER and SIGNAL circular connectors from LAPP. These are equipped with a specially coordinated EMC cable gland for servo and data cables.

Milestone for EMC: zeroCM® technology from LAPP

The zeroCM® technology from LAPP makes a key contribution to improved EMC in machines and systems. The new and patented cable design with a low-capacitance bundle construction with an opposite protective earth achieves one hundred percent electrical symmetry and improves electromagnetic compatibility. The first product is the ÖLFLEX® SERVO zeroCM.

Always EMC protected with the service from LAPP 

Electromagnetic interference cannot be seen, which is what makes it so insidious. It takes a lot of experience to detect it, ideally before it causes damage. LAPP has a comprehensive range of products to support its customers:

How you benefit as a customer:

How can unscreened cables and cables be screened afterwards?

If an unscreened cable is not possible in the system for various reasons, or if cables only need to be electromagnetically screened in certain sections of the system, the LAPP protective conduits can also be equipped with our SILVYN ® conduits as well with copper braids or wrapped in the 3M Scotch 1183 screening tape.

For these systems, LAPP offers a one- and two-part screening connection for connecting the copper braiding to a housing wall or a connection contact for looping through the cable shield.

How can EMC protection be improved?

To ensure optimum screening, cables can be fitted with double screening or installed in a copper or steel pipe. From an EMC perspective, these screens are completely sealed. LAPP SILVYN® offers you the optimum EMC protection. The EMC AS-CU protective conduit from the SILVYN® product brand is a metal protective conduit with copper braiding and is therefore suitable for particularly harsh environments with high electromagnetic requirements. The SILVYN® MSK-M BRUSH conduit gland with EMC protection and integrated strain relief rounds out your EMC-screened system.

Are there pre-assembled power, control, and data cables with EMC screening?

Poor EMC is often the cause of installation errors. For a long time, it was customary in industry to buy cables and plugs separately and only connect them when installing them in a machine or production plant, for example.

There are a few disadvantages to greater flexibility: processing quality often leaves a lot to be desired. For instance, if the installer cuts too deep when stripping and damages the core insulation or only partially connects the screening to the housing of the plug, causing EMC problems.

This is why the trend is towards ready-assembled cables, which we at LAPP sell under the name ÖLFLEX® CONNECT. The cable and plug are already connected ex works. Customers even receive drag chains fully equipped with cables and hoses, and LAPP also takes over the engineering work. Customers are therefore guaranteed to always receive optimal quality from a single source and can also concentrate on their own work, namely building machinery.

>> Contact the LAPP Tannehill team to learn more!