OnFilter CleanSweep EMI filters provide noise-free AC power to your sentive equipment in end-user installations. Innovative design accomplishes maximum noise suppresssion of signals polluting your power lines, freeing your equipment from harmful interference.
Clean power is essential for uninterrupted and problem free operation of electronic equipment. In our ever increasingly ‘electronic’ world,  electromagnetic interference (noise) becomes more prevalent and is routinely conducted through the power network and ground, causing reliability issues.
The design of the CleenSweep filters focuses on the properties of real-life signals on power lines and produces maximum reduction of the ‘worst offenders’ on these lines.
A wide range of filters is available, to cater for the diverse situations that may be encountered…..

Three phase filters can also be supplied. These are ‘made to order’ to suit your specific applications up to 30A/phase and in Delta or Wye configuration.
Servo motors and variable frequency motor drives are a well known source of noise and interference. We have filters specially optimised for these installations. See the section on Servo and VFD filters here.

Key Points

  • Cost effective.
  • Extremely simple to install.
  • Improve reliability of electronic equipment.
  • Block incoming noise and prevent mains contamination from your own equipment.
  • Reduce computer crashes.
  • Comprehensive range of filters available, up to 30A.
  • Single phase and 3 phase models.
  • Wide range of outlet connectors and configurations.


OnFilter mains filters are uniquely designed to deal with interference under real rather than laboratory conditions. They were developed after a careful study of the manner in which RF interference is transmitted through mains power distribution cables. The conclusions of this study has led to a filter design which is proven to be far more effective than those which are designed to meet EMC standards only. OnFILTER AC single phase filters provide effective EMI protection for electrical equipment powered by 50/60Hz, 110 to 250V sources.  These filters are especially effective where conventional EMI protection fails – at lower end of the spectrum.

Long cables in a power network affect the noise signal generated by equipment.  Distributed inductance and capacitance of the cables in addition to the skin effect reduce high-frequency content of the noise; however the same inductance and capacitance create resonant circuits that “ring” on sharp transient signals that are all too common on power lines and transform these short transients into longer low-frequency signals.  These low-frequency signals (generally, up to 1MHz) are not present during electromagnetic emission tests in a laboratory and thus are not controlled by the equipment’s own filters.
Filters can be ordered with a variety of option: connectivity (cable and outlets for different regions) and others.

Product Specification

  3A filter Single Phase 3 Phase Internal
 Rated Voltage (rms) 250v rms 110 ... 380vAC 110 ... 380vAC Ground
 Rated current (rms) 3A  10 ... 30A up to 30A N/A
Transient signal attenuation
Differential mode
Common mode









Continuous signal attenuation
Low frequencies
High Frequencies









 Power indication LED LED LED N/A

Size  (W x D x H)  mm.

Up to 20A
Over 20A


80 x 47x 127


157 x 153 x 75
157 x 254 x 75


157 x 254 x 75
157 x 254 x 75


51 x 35 x 20


In addition, to help quantify the extent of the noise, power line EMI adaptors are available which enable the user to connect an oscilloscope or spectrum analyser to the mains lines to study the power line noise characteristics

Associated Downloads

CleanSweep - a technical background. - Describes the cause and cure for mains noise,
Data sheet - OnFilter Single and 3 phase filters
Soldering irons and EOS dangers- Modern micro-circuitry is becoming more susceptible to electrical noise and potential damage from even the best soldering equipment. This paper discusses the causes and cures for this situation.