New Industry Products

Single-Phase EMI Filter for 277Vac/400Vdc Applications

June 26, 2019 by Scott McMahan

Schurter added the new FMAB HV series to its successful family of EMI filters for 1-phase systems. The new filter is suitable for applications requiring ac voltages up to 277V, such as 1-phase of the 3-phase 480Vac/277Vac wye system, typically used for lighting applications in North America. It is also rated for 400Vdc, a power infrastructure increasingly common in data centers and related equipment according to IEC 60950. The filter offers a high level of performance in a small compact package.

Today, more and more mixed ac and dc power infrastructures are used for the purpose of energy efficiency and/or improved power reliability. In such applications, the FMAB HV enables filtering on both the ac and dc sides of the power stream, albeit connected via the mains directly. It also enables filtering before and after conversion or stepped down for use at 250V.

As a result of its high symmetrical attenuation, the filter series is particularly suited for devices using semiconductors, which regulate high outputs for applications such as commercial coffee machines, hot water dispensing machines, and all types of industrial electronics.

Moreover, the compact, fully-enclosed housing offers optimized shielding via a very stable, flush mounting. Low leakage M5 and M80 variants are available for medical applications according to IEC/UL 60601-1.

The FMAB HV offers a current range from 1A to 20A at 277Vac / 277Vdc according to IEC standard, and 277Vac and 400Vdc according to UL/CSA standard. It has ENEC and cURus approval. The filters are available with quick-connect terminals (6.3mm x 0.8mm) and are screw mounted to the chassis.

The temperature range is from -40°C to 100°C. Versions with a built-in varistor for effective over-voltage protection are available on request.


  • Filter for 277Vac or 400Vdc applications
  • 1 stage
  • Compact filter with high symmetrical attenuation

Unique Selling Proposition

  • For high ac- or dc-voltages
  • Excellent symmetrical attenuation
  • Completely enclosed steel housing
  • Optional over-voltage protection


  • For 277Vac applications in North America WYE 480/277 volt system
  • For 400Vdc applications e.g. data center
  • Specially designed for applications with symmetrical noise caused by switching semiconductors
  • Suitable for use in equipment according to IEC/UL 60950
  • Suitable for use in medical equipment according to IEC/UL 60601-1