The Siemens 3RV1021-0FA15-ZW97 is a SIRIUS motor protection circuit breaker, designed for motor protection duty. It carries a rated continuous current of 0.5 A and a Class 10 trip characteristic, meaning it will trip within 10 seconds at 7.2× the thermal setting — appropriate for standard induction motor starts where the inrush transient is brief. Phase failure detection is built in, so a lost phase on a lightly loaded motor won't go unnoticed until the winding smokes.
Mounts via screw or snap-on onto 35 mm standard rail per DIN EN 50022. The 45 mm width matches a single modular device pitch, so it slots into a panel without stealing adjacent space. Screw terminals on the main circuit accept solid conductors from 0.5 mm² up to 6 mm² (stranded) and auxiliary wiring down to 0.5 mm² solid. Terminal torque and strip length follow standard practice — no oddball tooling needed.
Breaking capacity is 100 kA at 240 V, 400 V, 500 V, and 690 V AC — that's a full-range rating, not a derated curve. In a panel with high available fault current, this breaker coordinates cleanly without needing a current-limiting upstream device in most cases. The 100,000-cycle mechanical endurance on the main contacts means it outlasts the motor in a typical cyclic application.
Operates from -20 °C to +60 °C ambient, stores and ships from -50 °C to +80 °C. Shock rated at 25 g for 11 ms — survives the rough ride to site and the occasional hammer blow near the panel. IP20 on the front means it's protected against finger contact but not washdown; keep it inside the enclosure.