Please note we are still adding products to our new website. Can't see the product you need? Contact us on 01444 243 452 /

June 2021 – Types of EMI-RFI Filters

Published on: 24/06/2021

Discover the basics of EMI-RFI Filters and the various types available at GD Rectifiers

Types of Enerdoor EMI Filters by GD Rectifiers. EMI-RFI Filters types listed in rows - single phase EMI-RFI filters, three phase EMI-RFI filters and three phase plus neutral EMI-RFI filters.

What is an EMI-RFI Filter?

Electromagnetic interference is an electrical or magnetic interference that can degrade or damage the signal or a components functionality of electrical equipment, impacting the circuit performance. Electromagnetic interference filters can be either a device or an internal module, designed to reduce or eliminate interference to power supplies.


How do EMI-RFI Filters work?

EMI (electromagnetic interference) filters are also known as RFI (radio frequency interference) filters and are used to mitigate the high frequency electromagnetic noise from power and signal lines.

EMI-RFI filters are used to suppress interference generated by the device, or by other equipment, and to protect a device from electromagnetic interference signals present in the environment. Most EMI filters consist of components that suppress differential and common mode interference.

EMI filters generally feature a high frequency range and uses two types of components that work together to suppress signals; capacitors and inductors. Capacitors inhibit direct current and permits alternating current to pass. Inductors hold energy in a magnetic field as electric current is passed through it, reducing the total voltage.

Capacitors used in EMI filters are called shunting capacitors, they redirect current and high frequency away form a circuit or a component. The shunting capacitor then feeds the high frequency current/interference into the inductors. When the current passes through each inductor, the overall strength or voltage is reduced until the inductors reduce the interference to nothing (known as shorting to ground).


Types of EMI-RFI Filters

Single Phase Filters

Single phase EMI/RFI filters are used to bring electrical and electronic products into compliance with national and international EMC standards.

Enerdoor Single Phase EMI Filter by GD Rectifiers

Single phase filters are typically used in: conveyors, variable frequency drives, servo drives, automated machinery, medical equipment, packaging machines, printing machines, renewable energy devices and power supplies.


GD Rectifiers offers a range of single phase filters from Enerdoor that are available up to 690Vac. Enerdoor’s single phase filters carry CE, UL and CSA approvals and offer a current range from 1 to 75A with nominal voltage up to 250Vac. They also offer a dedicated low leakage current solution for medical applications. Various connections such as: IEC plugs, fastons, terminal blocks, cables, screws and DIN rail mounting for fast and easy installation within the enclosure are available.

Shop Single Phase EMI Filters


Three Phase Filters

Three phase filters provide high attenuation in a compact case with low leakage currents and are suitable for a wide range of applications. Three phase filters reduce unwanted electromagnetic interference noise within a conducted area of electromagnetic susceptibility and help maintain compliance with emission standards.

Enerdoor Three Phase EMI Filters by GD Rectifiers

Three phase filters are typically used in: servo drives, automated machinery, variable frequency drives, IT networks, medical equipment, CNC machinery, HVAC systems, recharging stations, renewable energy and UPS devices.

GD Rectifiers offers a range of three phase filters from Enerdoor with a current range from 1 to 300A and nominal voltage up to 690Vac. Enerdoor’s three phase filters are available with terminal block, cable, screw and busbar connections along with finger safe protection for screw and busbar options. In a three phase filter, DIN rail mounting provides fast and easy installation in to the enclosure.

GD Rectifiers works closely with Enerdoor to offer solutions in traditional TN and TNS networks and in specific applications such as IT power line configurations. We work to customised voltage, current, connection and attenuation specifications, offering solutions to satisfy numerous application needs.

Shop Three Phase EMI Filters


Three Phase Plus Neutral Filters

Three phase plus neutral filters offer very high differential and common mode attenuation in a compact case with high performance and a low frequency range.

Enerdoor Three Phase Plus Neutral EMI Filters

Three phase plus neutral filters are typically used in: CNC machines, laser equipment, multiple drive installations, woodwork machinery, medical machines, semiconductor machines, automated machinery, packaging machinery and conveyors.

GD Rectifiers offers a range of three phase plus neutral filters by Enerdoor, offering a current range from 1 to 200A with nominal voltages up to 600Vac. GD Rectifiers works with Enerdoor to offer customised voltage, current, connection and attenuation solutions and like with all filters, offer terminal blocks, cables, screws and busbar connections with DIN rail mounting.

Shop Three Phase Plus Neutral Filters


Typical Applications

EMI-RFI filters are widely used in applications, such as: automotive equipment such as battery chargers, energy management systems, computers, factory and machine automation equipment, industrial equipment, medical imaging/diagnostic/patient devices, exercise equipment, MRI rooms, test chambers/shielded rooms and many others.


GD Rectifiers is an authorised distributor the Enerdoor Group and distributes their complete range of EMI-RFI filters, harmonic filters, DC filters, parallel filers, medical and military filters, motor protection devices, power factor correction devices, voltage stabilisers, surge arresters, safety transformers, ignition transformers and custom filters


For further information on Enerdoor’s range of EMI-RFI filters or to discuss your requirements, please call our team on: 01444 243 452 or email:

Share Article

Related News

Arc-Flash Relays image
Harmonics in Electrical Power Systems
AHF Active Harmonic Filter
Littelfuse 10EV High Voltage Fuses
GD Distributor Image
Enerdoor Products
Enerdoor Three Phase EMI-RFI Filters by GD Rectifiers
CE Certification by GD Rectifiers
Enerdoor UL Approved Filters
Enerdoor's new power transformers
Meth Harmonic Detuned Reactors