What this breaker does in the nacelle
The Siemens SIRIUS 3RV2031-4RA10-ZX95 is a motor protection circuit breaker — the one that sits ahead of the contactor in a motor starter, watching for overload and short-circuit conditions. It's Class 10 trip, which means it will clear a stalled-rotor condition fast enough to protect a standard induction motor winding before the heat soak damages the copper. That 65 kA interrupting rating at 240 V and 30 kA at 400 V tells you it can handle a hard bolted fault on a 480 V distribution bus without the upstream breaker needing to coordinate. The 55 mm width and 149 mm depth fit a standard SIRIUS 3RV2 panel footprint — no surprises on the DIN rail.
Mounting and environment — built for the cabinet, not the bench
Screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715. Mounting position any, so you can lay this in a vertical or horizontal bus without worrying about the bimetal strip orientation. Operating temperature -20 to +60 °C; storage and transport -50 to +80 °C. That -20 °C floor matters if the panel sits in an unheated turbine nacelle or a cold warehouse. Clearances: 50 mm upwards, 50 mm downwards, 10 mm at the side, zero forwards or backwards. The M6 main contact terminals accept 2x 1–35 mm² or 1x 1–50 mm² solid or stranded — screw-type terminals, so you need a torque driver, not a spring-cage tool.
What the ratings mean for the panel
Rated operating voltage 20–690 V. Phase failure detection is built in; ground fault detection is not. The 15 hp at 230 V, 30 hp at 220/230 V, 60 hp at 460/480 V — these are the NEMA horsepower ratings for the motor it protects. The interrupting ratings at 500 V (5 kA,) and 690 V (2 kA,) drop off because the arc extinction gets harder at higher voltage. At 240 V no external fuse is required; at 400 V the breaker coordinates with a 160 A upstream fuse, at 500 V a 125 A fuse, at 690 V a 100 A fuse. That coordination data saves you the selectivity study time.