The Siemens 3RV1021-1AA15-ZX95 is a SIRIUS motor protection circuit breaker sized for a 1.6 A continuous current and rated for a 0.55 kW motor at 400 V AC. That 1.6 A is the full-load ampacity it carries without tripping — bump the load beyond that and the Class 10 bimetal curve starts its clock, opening in under 10 seconds at 7.2× rated current. Class 10 is the standard for standard induction motors; it protects the winding before the rotor stalls and cooks the insulation. The 100 kA breaking capacity holds across the full voltage range — 240 V, 400 V, 500 V, and 690 V AC — so this breaker clears a bolted fault upstream of the motor starter without welding its contacts shut. If one leg of a three-phase supply drops out, the breaker trips — that's a real help on a motor line where a single-phased winding can burn out before the overload relay notices. No ground-fault detection here, so keep a separate GFCI or RCD in the circuit if the installation code requires it.
Mount it in any position — vertical, horizontal, upside-down — the thermal curve doesn't care. Screw terminals on both the main and auxiliary circuits. The main terminals accept solid wire from 0.5 to 1.5 mm² (two per clamp) and stranded from 1.0 to 2.5 mm² (two per clamp). For the auxiliary / control circuit, the same terminal range applies. AWG 14 to 10 on the main contacts. That's enough for the 1.6 A motor branch plus a small control transformer downstream.