Overview

This guide applies to the use of capacitors, resistors, inductors and complete filter units for electromagnetic interference suppression. Electrical machines and devices can emit electromagnetic interference voltages that affect the power supply network. This interference in the high-frequency range can then be received by equipment connected to these power supply network or operated at a certain distance from the machine or equipment. The electromagnetic interference voltages can occur both between the conductors (phases) of the mains (symmetrical interference) and between conductors and earth (asymmetrical interference). These voltages can lead to electromagnetic radiation of the mains line. The electromagnetic disturbances can be reduced if low impedance paths are provided for the high-frequency currents close to their point of origin. This can be done by combining a high-impedance component that prevents the high-frequency currents from entering the power supply network, but has no noticeable effect on the current consumption. In various countries, legal limits apply to electromagnetic interference caused by electrical machines and devices in certain frequency ranges. An overview of these limits is given in the relevant EMC standards such as CISPR 11. Some electrical equipment requires a supply voltage that is free from electromagnetic interference beyond the specified requirements. In such cases, similar measures should be taken at the point of the power supply network close to the connection of the equipment. If the equipment is shielded (or is located in a shielded room), then interference suppression is generally carried out at any point where the power supply network is fed into the shielded environment. Compared with the previous edition, this edition contains the following main technical changes: - In 4.1, the example of the use of components for suppressing electromagnetic interference in a radio interference filter has been added; - In 7.1, the U-capacitors have been deleted; - In 7.1, the line voltage permitted for Y-capacitors has been increased to 500 V; - 7.2 - leakage current - has been revised. The responsible committee is DKE/K 623 "Funk-Entstörmittel" ("Capacitors and resistors for electronic equipment") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Document: references other documents

Responsible national committee

DKE/K 623 - Funk-Entstörmittel