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What is EMC?

EMC stands for ‘Electromagnetic Compatibility’, also known as ‘Electromagnetic Compatibility’. This term indicates how different devices in an electrical installation influence each other: ‘Being able to function properly in an electromagnetic environment, without disturbing the environment.’

EMC problems therefore always involve one or more disruptive consumer(s) (‘emission’) and a fault-sensitive consumer, or ‘victim’ (‘immunity’). The disruptive consumer always disturbs the victim via a coupling or radiation. Read more about EMC and the microwave absorbers. .

Does EMC belong to Power Quality?

In practice, Power Quality usually ends at the 50th harmonic (2500/3000Hz). Conduction EMC is generally standardized from 150kHz to 30MHz. However, with the emergence of power electronics in LED lighting, PV inverters and frequency converters, the boundary between Power Quality and EMC is beginning to blur. These electronics have a high switching frequency, which ensures harmonic currents and voltages in the spectrum above 2500Hz. These high frequency harmonics are also called supraharmonics.

What is Electromagnetic Emissions and Immunity?

Electromagnetic immunity says something about how well a device can operate in an environment with electromagnetic disturbances.

Electromagnetic emission says something about how much electromagnetic disturbance a device generates. This is also known as Electromagnetic Interference (EMI). We can distinguish the following types of emission:

  • Conduction: Via cables, often via the earth (PE)
  • Radiation: directly through the air through (accidental contact between) antennas

What is the difference between EMC and EMI?

Interference means: Malfunction. Electromagnetic interference therefore refers to the disturbance of an installation or device. EMC refers to the interplay (tolerance) of the entire installation.

What do the standards say about EMC?

Any electrical device sold must comply with the European EMC Directive 2014/30/EU. Devices that comply with this are provided with a CE marking by the manufacturer. Various standards of the IEC61000 series also apply to equipment, depending on the frequency and whether the emission is through conduction or radiation. The known standards (net code, NEN1010) do not mention any specifications for EMC.

How do you prevent EMC problems?

Achieving EMC is becoming increasingly difficult these days due to the amount of electronics in and outside the installation. Think, for example, of telephone communication (3G, 4G, 5G) but also of disruption by, for example, frequency controllers. However, there are some ‘rules of thumb’ that should be adhered to in order to reduce the chance of EMC problems. These are, for example, applying the correct cabling, grounding principle and separating power and signal cables. In some cases, the standard steps are not sufficient and additional filtering is required.

How do you solve EMC problems?

The first step with EMI is always measuring. However, EMI measurements cannot be made with typical power quality meters. This requires special meters with a large bandwidth, such as oscilloscopes. Once the problems have been identified, changes can be made to the installation: the disrupting device can be isolated or the affected device can be made extra immune. It is also possible to apply EMC/EMI filters. For this, you can contact DMAS. We will definitely solve your problem!