What this part is and what it does
The Siemens 3RV2011-1BA40 is a SIRIUS motor protection circuit breaker, designed to protect three-phase motors against overload and short-circuit. It's a Class 10 device, meaning it trips within 10 seconds at 7.2× the thermal setting — fast enough to protect standard induction motors during a locked-rotor event. The breaker includes phase failure detection, so a lost phase won't let the motor single-phase and burn out. Breaking capacity is 100 kA at 400 VAC and 500 VAC, and 10 kA at 690 VAC. That's enough to handle high-fault utility feeds without needing an upstream current-limiting fuse in most industrial panels. For installations where the available fault current exceeds the breaker's interrupting rating, the spec calls for gL/gG backup fuses: 25 A at 400 V or 500 V, 20 A at 690 V.
Mounting and integration
Mounts on 35 mm DIN rail per DIN EN 60715, using either the snap-on latch or a screw for vibration resistance. The 45 mm width matches the standard SIRIUS 3RV2 footprint — it'll sit tight against a contactor or overload relay in a motor starter row. Mounting position is any orientation, which simplifies panel layout. Clearance distances: 50 mm above and below, 30 mm to the sides, zero forwards or backwards. That's the breathing room for arc flash and heat dissipation — don't crowd it. Main circuit connection uses ring cable lugs with M3 screws on the main contacts. Dimensions are 97 mm deep by 97 mm high by 45 mm wide. Fits in a standard 200 mm deep enclosure with room for wiring behind it.