Protection relays

Basic functions:

  • Minimum voltage relays
  • Maximum voltage relays
  • Differential voltage relays
  • Minimum current relays
  • Maximum current relays
  • Differential current relays
  • Interval voltage relays
  • Frequency protection relays
  • Phase sequence relays


  • High galvanic separation
  • No auxiliary supply needed, stand alone
  • High reliability, no maintenance due to reliable and proven electromechanical technology
  • Strong ability to withstand high overloads
  • Equipped with weld no transfer
    contacts for critical applications

For On-Board applications:

  • Traction brake monitoring relay
  • Traction overcurrent relay
  • Traction isolation breakdown relay
  • Catenary min. voltage detection relay
  • Catenary max. voltage detection relay
  • Wheel slip relay
  • Insulation breakdown relay
  • Battery monitoring relay
  • Motor/alternator monitoring relay
  • Pre-load filter detection relay
  • Ground fault detection relay

For Trackside applications:

  • Directional current detection relay (reverse current detection in power distribution)
  • Catenary voltage (1500 V) detection relay
  • 3rd rail voltage detection relay
  • Substation ground fault detection relay
  • Heat tracing cable surveillance relay
  • Current overload relay (15000 A)
  • Voltage, current, ground & insulation fault detection relays

    Protection relays are often the last barrier to protect rolling stock and trackside equipment in the event of upstream protection system failure. They do not require auxiliary supply. Their mechanical life of 100 million operations exceed train life. Protection relays are designed on an electromechanical technology providing high reliability with friction free mobile armature and maintenance free. It has a strong ability to withstand high overloads due to its magnetic…