Siemens SIRIUS 3RN2 Thermistor Motor Protection Relay 3RN2012-2BW30, 24 V AC/DC, 1 Sensor Circuit, 1NO+1NC, Screw Terminals, DIN Rail

Prevent motor burnout from overheating with the Siemens 3RN2012-2BW30 thermistor motor protection relay. This compact device monitors PTC thermistor sensors embedded in motor windings and trips the control circuit when the temperature exceeds safe limits, protecting your motor from insulation damage and downtime.

Who is it for

Maintenance engineers, panel builders, and machine OEMs who need reliable thermal protection for motors in industrial applications such as pumps, fans, compressors, and conveyors.

Main features

• Monitors one thermistor sensor circuit (PTC type) for direct winding temperature measurement
• Wide control supply voltage: 24 V AC/DC
• One NO and one NC auxiliary contact for flexible signaling and interlocking
• Selectable reset mode: automatic, manual, or remote
• Screw terminal connections for secure wiring
• Mounts on standard 35 mm DIN rail

Specifications

• Product type: Thermistor motor protection relay
• Series: SIRIUS 3RN2
• Control supply voltage: 24 V AC/DC
• Number of sensor circuits: 1
• Auxiliary contacts: 1 NO + 1 NC
• Reset function: AUTO / MANUAL / REMOTE
• Connection type: Screw terminals
• Mounting: DIN rail 35 mm
• Operating temperature: -25 to +60 °C
• Storage temperature: -40 to +85 °C
• Rated insulation voltage: 300 V
• Rated impulse withstand voltage: 4 kV
• Degree of protection: IP20
• Auxiliary contact current (AC-15, 230 V): 3 A
• Auxiliary contact current (DC-13, 24 V): 1 A

Tips

Pair with PTC thermistor sensors embedded in the motor windings for direct temperature monitoring. Use the remote reset function to integrate with PLC control systems.