Siemens SIRIUS 3RU2 Thermal Overload Relay 0.9-1.25 A, Class 10, S00, Screw Terminals, 1NO+1NC 3RU21160KB0

Motor protection against overloads and phase failure is critical in industrial control panels. The Siemens SIRIUS 3RU21160KB0 thermal overload relay offers reliable protection for three-phase motors with a current setting range of 0.9 to 1.25 A. It is part of the SIRIUS 3RU2 series, designed for direct mounting on contactors or standalone installation, ensuring flexibility in various applications.

Who is it for

This relay is ideal for electrical engineers, panel builders, and maintenance technicians who need dependable motor protection in compact spaces. It suits small to medium-sized machines, conveyor systems, pumps, and fans where space is limited and precise overload protection is required.

Main features

• Thermal overload relay with adjustable current setting from 0.9 to 1.25 A
• Class 10 tripping characteristic for normal motor starting conditions
• Compact size S00 for space-saving installation
• 3-pole design with screw terminals for secure wiring
• 1 NO + 1 NC auxiliary contacts for signaling and control
• Manual/automatic reset function for flexible operation
• Direct mounting on contactors or standalone with DIN rail adapter (adapter not included)
• High rated insulation voltage up to 690 V for versatile use
• IP20 protection for use in enclosed control panels
• Complies with IEC 60947-4-1 and IEC 60947-5-1 standards

Specifications

• Product type: Thermal overload relay
• Series: SIRIUS 3RU2
• Current setting range: 0.9 - 1.25 A
• Trip class: Class 10
• Size: S00
• Number of poles: 3
• Mounting type: Direct mounting to contactor / standalone
• Auxiliary contacts: 1 NO + 1 NC
• Connection type: Screw terminals
• Rated insulation voltage (Ui): 690 V
• Rated impulse withstand voltage (Uimp): 6 kV
• Rated operational voltage (Ue): 690 V AC
• Protection class: IP20
• Ambient temperature (operation): -20 to +60 °C
• Reset function: Manual / Automatic
• Standards: IEC 60947-4-1, IEC 60947-5-1

Tips

For optimal protection, set the current adjustment dial to the motor's full load current. Ensure the relay is mounted in a clean, dry enclosure to maintain IP20 protection. When using automatic reset, verify that the control circuit can safely handle unexpected restarts.