Harmonic filter for drives RHF

Harmonic mitigation of variable frequency drives

RHF-A und RHF-B – die hocheffizienten zweistufigen passiven Oberschwingungsfilter werden eingesetzt um die durch einen Frequenzumrichter verursachten Oberschwingungen zu eliminieren

The REVCON® harmonic filter RHF is passive filter, designed to reduce the harmonic distortion of a load fed by a 6-puls rectifier. This kind of load is very common in drive applications.

The REVCON RHF-5P/8P is a passive filter. It is not tuned to individual frequencies like an absorption circuit, but works like a bandstop filter, reducing all low harmonics up to the 200th significantly.

For a comparison, the circuit feedbacks of variable frequency drives and regen units are shown evaluated by the THiD (total harmonic distortion of the line current) at the nominal point of the electric rectifier/inverter in the following table:


Unchoked 6-puls rectifier Choked 6-puls rectifier Choked 6-puls rectifier with RHF-8P Choked 6-puls rectifier with RHF-5P
>80% ~40% <8% <5%

The passive harmonic filter REVCON RHF-A/B is an effective, inexpensive and very efficient (>98.5%) action in order to reduce harmonic distortion of a drive system.


  • very compact size
  • THDi below 5%
  • output range 4kW to 440kW
  • high efficiency
  • user-friendly start-up, as no programming or settings are required
  • maintenance free!

Harmonic filter for feed and regen unit RHF-R
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