What it is and what it does
The Siemens 3RV1021-0GA10 is a SIRIUS motor protection circuit breaker, designed specifically for protecting three-phase motors against overload and short-circuit. It's a 3-pole unit with screw-type terminals for the main and auxiliary circuits. Rated at 0.63 A continuous current, it's sized for small motor loads — think fractional-horsepower pumps, fans, or conveyor drives. The Class 10 trip characteristic means it will disconnect within 10 seconds at 7.2x the rated current, matching the thermal curve of a standard induction motor during a stall or jam. Breaking capacity is a solid 100 kA at 400 V AC, and it holds that same 100 kA at 240 V, 500 V, and 690 V AC. That's high fault-current capability for a breaker this size — it can sit downstream of a large transformer without needing a current-limiting upstream device in most panels. It includes phase failure detection, so if one phase drops out on a three-phase motor, the breaker trips before single-phasing cooks the winding. No ground fault detection on this unit — that's handled separately if needed.
Mounting and panel fit
Mounts via screw or snap-on onto a standard 35 mm DIN rail per DIN EN 50022. The 45 mm width means it takes up a single 45 mm slot on the rail — standard footprint for this class. Depth is 96 mm, height 97 mm. Zero clearance needed at the back or sides for heat dissipation, so you can pack breakers tight in a row. Accepts solid and stranded wire: 2x (1 to 2.5 mm²) or 2x (2.5 to 6 mm²) per terminal. AWG equivalents are 2x (14 to 10). That covers most control-panel wiring for a motor circuit of this size.
Environmental and compliance
Operates from -20 to +60 °C, stores and ships from -50 to +80 °C. IP20 on the front face — finger-safe from the panel front, but not washdown-rated. Shock rated at 25g for 11 ms, so it holds up in vibrating machinery. Substance prohibition date of 01.05.2012 aligns with RoHS compliance timelines. Surge voltage resistance is 6 kV, consistent with IEC 60947-2 coordination requirements for industrial panels.