Interference Frequencies Detection for the Railway domain

RA - Railway current sensors

The RA product family serves the purpose of detecting interference frequencies and relies on Rogowski technology (air-core). It enables the measurement of alternating components within a specified bandwidth contained in a continuous primary current.

RA sensors offer a bandwidth ranging from 20 to 3000 Hz. It is important to note that LEM does not include an integrator as part of the RA product range.

These RA current sensors are primarily designed and customized for railway applications.

RA – Features and benefits

RA railway current sensors

Main characteristics

  • Air-core technology (Rogowski measuring principle)
  • Insulating plastic case recognized according to UL 94-V0


  • No insertion losses
  • Current overload capability

Typical applications

RA current sensors are specifically designed and manufactured for use in railway applications, finding common use in both fixed installations and onboard trains and locomotives. 

These sensors play a key role in ensuring the safe and efficient operation of electrical systems within the railway domain.

It is usual to find RA sensors in the following applications:

  • Single or three phase inverters
  • Propulsion and braking choppers
  • Propulsion converters
  • Auxiliary converters
  • Battery chargers

LEM RA – Download & Technical Characteristics

Product Document Primary nominal RMS voltage Mounting Op. Temperature
RA 1005-S


1000 A Panel -25 to 70 °C
RA 2000-S/SP1


3000 A Panel -25 to 70 °C


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