The Siemens 3RB1015-1RB0 is an electronic overload relay from the SIRIUS 3RB10 series, rated for a motor current range of 0.1...0.4 A with a Class 10 trip characteristic. It uses a screw connection and is designed for direct mounting on a contactor of size S00. The relay offers only manual reset, meaning it locks out after a trip and requires a deliberate push to re-energize — a deliberate safety choice for applications where automatic restart after an overload could be hazardous.
The 0.1...0.4 A current range covers fractional-horsepower motors — think small pumps, fans, or conveyor drives where the full-load amps sit in that window. The Class 10 trip class means it will disconnect within 10 seconds at 600% of the set current, which is standard for standard induction motor starting (not high-inertia loads that need Class 20 or 30). The manual-reset-only design suits unattended machinery where an automatic restart after a fault could be a safety risk; if your application requires automatic reset, this is not the variant. Size S00 is the smallest SIRIUS contactor footprint, so the relay mounts directly onto the contactor without additional DIN-rail space — a clean, compact assembly for a panel with tight fill factor.