Siemens SIRIUS 3RU2136-4FB0 Thermal Overload Relay, 28-40 A, Class 10, 3-Pole, Screw Terminals

Thermal overload relay for reliable motor protection in industrial applications, offering precise current-dependent tripping in the 28–40 A range. This SIRIUS 3RU21 series device provides phase failure sensitivity and a trip indicator, ensuring motors are safeguarded against overheating and phase loss.

Advantages

Direct mounting to Siemens contactors (e.g., 3RT203) simplifies installation and reduces wiring. The manual/automatic reset function and clear trip indication enhance operational convenience. Screw terminals ensure secure connections in demanding environments.

Suitable for

• Protecting three-phase motors up to 40 A in industrial control panels
• Applications requiring reliable overload protection with phase failure detection
• Integration with SIRIUS modular system for motor starters

Key specifications

• Current setting range: 28–40 A
• Overload class: CLASS 10
• Number of poles: 3
• Auxiliary contacts: 1 NO + 1 NC
• Rated insulation voltage: 690 V AC
• Degree of protection: IP20 (terminals)
• Operating temperature: -20 to +60 °C

Recommendations

For optimal performance, pair with Siemens SIRIUS contactors and use appropriate cable cross-sections as per installation guidelines. Ensure proper setting of the current dial to match the motor's full load current.