Delta TRD4 Compact electro-mechanical tripping relays


The Delta TRD4 is a high speed, high burden electro-mechanical tripping relay for power utility protection and control applications. The TRD4 is built on the Delta relay platform providing high performance and reliability while reducing production and supply lead times. Application of the Delta TRD4 multi-contact high-speed trip relays ensures fast operation of less than 10 ms. The Delta TRD4 relay provides a robust and reliable high speed interface between the protection system and the circuit breaker. A more economical alternative to traditional tripping relays the Delta TRD4 provides a compact, flexible and high performance solution while meeting relevant IEC standards. A wide voltage range, high burden operation and standard hand reset flag reduces the number of model variations. The Delta range is packaged in a size 2, 2U high case that may be flush panel, rack or rail mounted. A plug in terminal block is provided to allow panel pre-wiring. Where more than 4 contacts are required refer to the Alpha Range Technical Bulletin.


  • Less than 10ms operate time
  • High burden operation to comply with capacitor discharge test requirements
  • 4 heavy duty contacts
  • Self-reset contact version
  • Latching contact version with hand and electrical reset
  • Hand-reset electro-mechanical flag
  • Rated operate voltages available for 24, 30/32, 48, 110, 125, 220, 240 or 250 Volts DC nominal auxiliary supplies
  • Panel, rack or rail mount options
  • Compact size 2, 2U high case
  • Plug-in terminal block
  • M4 screw terminals
  • Relay operate LED standard
  • Magnetic arc blowouts standard





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