It combines a circuit breaker and overload relay in one device, sized for protecting three-phase motors against short-circuit and overload conditions. Rated for a switching frequency of 15 operations per hour at AC-3 duty (and AC-3e), it handles the typical start-stop cycles of conveyors, pumps, and compressors without overheating the bimetal trip.
The 100 kA breaking capacity at 400 V AC (and at 240 V, 500 V, and 690 V AC) means this breaker can safely interrupt a fault current up to 100,000 A at those voltages without welding its contacts or rupturing the arc chamber. At 230 V it is rated for 0.2 kW motor protection, which translates roughly to a 0.25 hp motor at that voltage. At 460/480 V the rating is 1 hp; at 575/600 V it drops to 0.5 hp. The 1.25 A setting at 480 V and 600 V confirms this is a small-motor breaker — sized for fractional-horsepower drives, not main feeders. Storage range of -50 to +80 °C means the spare can sit in a cold toolbox or hot truck without damage.
Main circuit terminals are screw-type, accepting 2×(1 to 2.5 mm²) or 2×(2.5 to 10 mm²) solid or stranded wire. The main contact screw is M4, requiring a 5 to 6 mm diameter screwdriver shaft. These are standard panel-building specs — no special tooling needed.
The closest functional peer is the 3RV1011-1HA10, which shares the same SIRIUS motor-protection class and Class 10 trip characteristic. The 3RV2021-0KA10 is the 45 mm wide frame; the 3RV1011-1HA10 is a different frame size. They are not drop-in interchangeable — verify the mounting footprint and terminal layout before substituting on an existing panel layout. For a new design, either works; for a retrofit, measure the existing cutout.