Siemens SIRIUS 3RU1146-4LB0 thermal overload relay protects 3‑phase motors by interrupting current when the load exceeds the preset range, designed for mounting on a compatible SIRIUS contactor (Size S3). It provides 1 normally open and 1 normally closed auxiliary contact (1NO+1NC), with screw terminals for both the main and auxiliary circuits and a Manual-Automatic-Reset option. The overload relay covers a current range of 70–90 A (with a typical full-load current around 77 A) and is rated for up to 690 V AC, Class 10 thermal protection, making it a compact, reliable motor-protection solution for panel installations.
