CTD4-U relay – Multifunction customizable timer, 4 pole


Plug-in electronic railway customizable timer relay with four change-over contacts. Fully customizable according customer’s requirements concerning timing diagram and delay type. Almost any timing diagram is possible: for example time delays with delay on pull-in, on drop-out or both, symmetrical or asymmetrical flashing, 1-shot, 2-shot, 3-shot etc. or a combination of all these. Delay/pulse times are adjustable with 1 or 2 lockable knobs. The relay can also be supplied with fixed delay/pulse times (no knobs).
The relay has standard four change-over contacts which work according the timing diagram. Also 2 instantaneous change-over contacts and 2 timer change-over contacts are possible, to cover virtually all needs. Besides being activated by a voltage level, it is possible to activate the relay via a command input as well. The relay is equipped with two LEDs which indicate the presence of power supply and energizing of the coil. Also standard equipped with magnetic arc blow-out for high breaking capacity and long contact life.
The construction of the relay and choice of materials makes the CTD4-U relay suitable to withstand low and high temperatures, shock & vibrating and dry to humid environments. No external retaining clip needed as integrated ‘snap-lock’ will hold relay into socket under all circumstances and mounting directions.


These relay series are designed for demanding rolling stock applications. The CTD4-U relay can be used in all Railway applications where a standard or non-standard timer function is necessary.


  • Fully customizable timer relay
  • Compact plug-in design
  • 4 time delayed C/O contacts or 2 time delayed C/O contacts and 2 instantaneous C/O contacts
  • Delay/pulse times adjustable with 1 or 2 lockable knobs
  • Also available with fixed delay/pulse times (no knobs)
  • Delay/pulse times: between 0 s…∞ (no limits)
  • Magnetic arc blow-out
  • Two LEDs for status indication
  • Suitable for DC and AC voltage


  • Flat, square and silver plated relay pins for excellent socket connection
  • Wide range of sockets
  • Integrated snap lock
  • Transparent cover
  • Optional positive mechanical keying relay to socket
  • Flexibility by many options

Railway compliancy

  • EN 50155 Electronic equipment used on rolling stock for railway applications
  • IEC 60571 Electronic equipment used on railway vehicles
  • IEC 60077 Electrical equipment for rolling stock in railway applications
  • IEC 60947 Low voltage switch gear and control gear
  • IEC 61373 Rolling stock equipment – Shock and vibration test
  • IEC 60947-5-4 Electromechanical components for control applications. This standard examines both coil and contact specifications in depth
  • EN 50121 Electromagnetic compatibility for railway applications
  • NF F 16-101/102, EN 45545-2 Fire behaviour – Railway rolling stock
  • NF F 62-002 On-off contact relays and fixed connections






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