The Siemens SIRIUS 3RV1031-4GA10-ZW96 is a 3-pole motor protection circuit breaker rated for 45 A continuous current, with a 22 kW motor rating at 400 V AC. It's a Class 10 thermal-magnetic trip device, meaning it clears a locked-rotor fault fast enough to protect standard induction motors from overheating during start-up. Phase failure detection is built in, so a single-phased motor won't cook while the breaker holds.
Breaking capacity — what it handles at line voltage
This breaker's interrupting rating drops as line voltage climbs: 100 kA at 240 V AC, 50 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC. At 400 V — the most common industrial motor voltage — 50 kA covers nearly any installation with a transformer upstream. The 690 V figure (4 kA) is the limit if you're running on a 690 V line; verify your available fault current stays under that.
Mounting and wiring
Snaps onto 35 mm DIN rail per EN 50022 — screw and snap-on mounting, any position. The 55 mm width and 140 mm height are standard for this SIRIUS frame size; depth is 149 mm, so account for that behind the panel door. Main circuit terminals are screw-type box terminals accepting 2x (0.75…16 mm²) solid or 2x (0.75…25 mm²) stranded, with a single terminal taking up to 35 mm² stranded. Auxiliary and control circuit terminals are also screw-type. Front face is IP20 — fine inside an enclosure, not for wet areas.
Thermal management
Total power dissipation in hot operating state is 29 W, or 9.7 W per pole. That's moderate for a 45 A breaker — enough to consider in a sealed, uncooled enclosure with multiple devices ganged together. Ambient operating range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Shock rated at 25g for 11 ms.