ABB RA5-1 Interface Relay

ABB RA5-1 Interface Relay is a compact, plug-in device that translates a low-power 24 V DC control signal from a PLC into the higher current required to energize ABB A9–A110 contactor coils. The unit houses a miniature electromechanical relay with a normally open contact and features two input terminals (E1 and E2) for the control coil, including polarity-reversal protection, plus two output pads (A1 and A2) that connect to the contactor coil. It is designed to receive 24 V DC signals from PLCs or other sources and deliver sufficient current to energize the coil of the relevant ABB contactors, enabling straightforward interfacing between logic-level controls and motor starters. For reliability, surge suppression is provided for the interface-relay coil. The RA5-1 is catalogued under ABB's Motor Protection and Control range and is identified by the part number 1SBN060300R1000. This combination makes it ideal for control panels where a low-power PLC output drives ABB A9–A110 contactor coils, providing isolation and a dedicated interface function without requiring direct energization of heavier coil circuits.