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.

EMC solution HK2013

Interference suppression filters with integrated surge protection

Interference suppression filters with integrated surge protection

Interference suppression filters with integrated surge protection perform two tasks: they absorb transient overvoltages and also limit high-frequency interference voltages.

Various designs are available:

SFP DIN rail module

  • Interference suppression filter and type 3 surge protection
  • Floating remote indication contact
  • Optical status indicator
  • DIN-rail-mountable
  • 5 A to 20 A nominal load current

TERMITRAB terminal block

  • Mains filter and surge protective device for MCR signals
  • With spring-cage connection
  • Protection for two conductors with common reference potential
  • For 24 V grid systems
  • DIN-rail-mountable
Interference suppression filters NEF 1-6, NEF 1-10

Interference suppression filters or mains filters

Interference suppression filters or mains filters

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.

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.

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.