What it is and what it does
The Siemens 3RV1011-0KA15-0BA0 is a SIRIUS motor-protective circuit breaker sized for a 0.37 kW motor at 400 V AC. It carries a continuous rated current of 1.25 A and a Trip Class 10, meaning it trips within 10 seconds at 7.2× the set current — standard protection for standard-start induction motors driving pumps, fans, or conveyors. The overload release is thermal (bimetal), the short-circuit trip is magnetic. Phase failure detection is built in, so a lost phase on the line side will trip the breaker before the motor single-phases to failure.
Breaking capacity and mounting
Rated breaking capacity is 100 kA at 240 V, 400 V, and 500 V AC, dropping to 2 kA at 690 V AC. That 100 kA figure covers most industrial distribution panels fed from a transformer of typical impedance — the breaker can interrupt a bolted fault at the bus without upstream fuses needing to clear first. Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022. Width is 45 mm, height 90 mm, depth 81 mm — fits a standard 45 mm slot in a motor control center or panel. IP20 on the front; no washdown rating, so keep it inside the enclosure.