Siemens 3RU2126-1HB0 Overload Relay

Siemens 3RU2126-1HB0 is a 3-pole thermal overload relay in the S0 size of the SIRIUS 3RU2 family, designed to mount to Siemens 3RU2 contactors for inverse-time motor protection. It covers a current rating range of 5.5–8.0 A and is Class 10 rated, providing reliable protection against overload conditions. The device uses screw-terminal connections on both the main circuit and the auxiliary circuit and supports a manual-automatic-reset mode with a trip indicator to show when protection has actuated. It includes phase failure detection (Yes) and does not provide ground fault detection (No). Electrical insulation is rated for 690 V, with a surge resistance of 6 kV, and the unit carries an IP20 front-protection rating. Ambient operating temperature is -40 to 70°C, and typical total power loss is about 6 W. An auxiliary switch is included, and the assembly is intended for mounting onto the corresponding 3RU2 contactor frame for compact motor-protection configurations.