SIEMENS SIRIUS 3RU2126-1KB0 Thermal Overload Relay 9.0-12.5A Class 10, Screw Terminals, 1NO+1NC

The SIEMENS SIRIUS 3RU2126-1KB0 thermal overload relay protects three-phase motors from overload, phase failure and asymmetry. Its current setting range of 9.0 to 12.5 A and CLASS 10 tripping characteristic suit standard industrial motor starting duties. Direct contactor mounting on SIRIUS S0 contactors saves panel space and simplifies wiring.

Highlights

• Current setting range: 9.0–12.5 A
• Tripping class 10 for normal motor starts
• 3-pole main circuit with screw terminals
• Auxiliary contacts: 1 NO + 1 NC
• Manual/automatic reset and stop function
• Mounts directly on SIRIUS S0 contactors

In daily use

The relay responds to sustained overloads and phase loss, opening its NC contact to drop the contactor and stop the motor. The NO contact can signal a PLC or indicator. After tripping, the operator can reset manually or configure automatic reset. The transparent cover allows checking the setting dial without opening the panel.

Full specifications

• Product type: Thermal overload relay
• Series: SIRIUS 3RU21
• Frame size: S0
• Rated operational voltage: up to 690 V AC
• Rated insulation voltage: 690 V
• Rated impulse withstand voltage: 6 kV
• Main circuit connection: screw terminals
• Auxiliary circuit connection: screw terminals
• Mounting: contactor mounting or stand-alone with adapter
• Ambient operating temperature: -20 to +60 °C
• Protection class: IP20

Final note

Choose this relay for reliable motor protection in industrial control panels where SIRIUS S0 contactors are used.