INTERFACE RELAY (ABB CR-U024DC3L) 24VDC/250VAC, 10A, 3 c/o

A robust, "ice-cube" style industrial relay with circular pins. Features an integrated blue test button (indicating DC) for manual actuation and a front-facing LED for status indication.

• dimensions: 35 mm x 35 mm x 54.4 mm

• weight: 0.083 kg

• material: cadmium-free contact material, robust plastic housing

• color: grey housing with blue test button

• mounting: puggable design, requires a compatible 11-pin socket (specifically PELECOMMRAB12 / CR-U3S)

• control/Coil: 24 V DC rated control supply voltage

• output/contacts: 3 c/o (SPDT) contacts

• electrical Rating: rated 250 V AC / 10 A per pole

• compatibility: designed to snap securely into the ABB CR-U3S socket

  
  
  
  
  

This device is an electromechanical interface relay, it's a remote-controlled switch. It allows a low-power control signal (like 24V from a computer or PLC) to switch on/off higher-power circuits (up to 250V AC) without the two circuits ever electrically touching each other.

How it Works:

• input: when 24V DC is applied to the coil, it creates a magnetic field.
• action: this magnet physically pulls the internal contacts from their resting position to their active position.
• result: this mechanical movement opens or closes the connected output circuits, turning devices like motors, lights, or heaters on or off.

Key Applications:

• watsan : acts as a level control interface between a float switch in a water bladder and the main supply pump. The float switch sends a low-current 24V signal to this relay, which then triggers the heavy-duty contactor to start the pump, preventing high currents from burning out the delicate float switch.
• operating theater HVAC: Controls the ventilation mode switching. A wall switch in the OT energizes this relay to switch fans from "Standby" to "Surgery Mode" (increasing positive pressure) without routing high-voltage cables to the user control panel.
• cold chain : Used in protection circuits to disconnect vaccine fridges or trigger an alarm if a temperature monitoring relay detects a fault, ensuring vaccines are not exposed to freezing or heating.
• generator automation: Provides the "remote start" signal (dry contact) to a backup generator when the main power monitoring system detects a grid failure.

Maintenance function: the built-in blue manual test button is critical for setup and troubleshooting. It allows a technician to physically force the relay to switch without needing to program the controller or run wires, verifying that the downstream equipment is working correctly.