Interference suppression filters and mains filters to limit interference voltages

Interference suppression filters for safe power supply

Interference suppression filters and mains filters limit pulse-like, high-frequency interference voltages caused by mechanical or electronically triggered switching operations. If interference voltages are not limited, they spread via the cable network and electrically conductive connections. This can result in data errors, uncontrolled functions, and system crashes. Mains filters ensure an EMC-compliant power supply by limiting interference voltages.

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Your advantages

  • Protection against pulse-like and high-frequency voltages using filters with integrated surge protection
  • Large number of fields of application due to various different attenuation curves
  • Flexible designs – can be used in control cabinets and at the workplace
  • Compact protection using symmetrical and asymmetrical filter circuit
Entstörfilter mit integriertem Überspannungsschutz für Netz- und Signalanwendungen


Entstörfilter mit integriertem Überspannungsschutz

Entstörfilter mit integriertem Überspannungsschutz übernehmen zwei Aufgaben: Sie absorbieren transiente Überspannungen und begrenzen zudem hochfrequente Störspannungen.

Verschiedene Bauformen stehen zur Verfügung:

Tragschienenmodul SFP

  • Entstörfilter und Typ-3-Überspannungsschutz
  • Potenzialfreier Fernmeldekontakt
  • Optische Statusanzeige
  • Tragschienenmontabel
  • 5 A bis 20 A Nennlaststrom

Reihenklemme TERMITRAB

  • Netzfilter und Überspannungsschutzgerät für MSR-Signale
  • Mit Federkraftanschluss
  • Schutz für zwei Leiter mit gemeinsamem Bezugspotenzial
  • Für 24-V-Netzsysteme
  • Tragschienenmontabel
Interference suppression filter (mains filter) on a DIN rail

Interference suppression filter (mains filter)

Interference suppression filter with dedicated filter circuit

Interference suppression filters or mains filters with a dedicated filter circuit protect against both symmetrical and asymmetrical disturbance variables.

NEF DIN rail module

  • Interference suppression filter
  • DIN-rail mountable
  • 1 to 10 A nominal current

TERMITRAB terminal blocks with integrated interference suppression capacitor are suitable for applications where asymmetrical protection is sufficient.

Example interference suppression filter circuit (filter circuit diagram)

Example mains filter circuit

Operating principle of filter circuits

Filtering of symmetrical disturbance variables X

Interference voltages between the phase and neutral conductor are filtered.

Filtering of asymmetrical disturbance variables Y1 Y2

The respective negative phase-sequence grounded interference voltages from the phase conductor to PE and from the neutral conductor to PE are filtered.

Typical characteristic curve for an interference suppression filter (characteristic curve field diagram)

Typical characteristic curve for an interference suppression filter

Effective range of mains filters

An attenuation characteristic curve diagram illustrates the effective operating range of mains filters. The relevant frequency-dependent attenuation can be read according to the symmetrical or asymmetrical filter circuit.