The Siemens 3RV1021-1CA15-ZW97 is a SIRIUS motor protection circuit breaker designed for motor protection, rated at 2.5 A continuous current with a Class 10 trip characteristic. It provides phase failure detection and offers a breaking capacity of 100 kA at 400 V AC, making it suitable for high-fault-current industrial panels. The unit mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, and the front face carries an IP20 protection rating.
Key Ratings & What They Mean
The 2.5 A continuous current rating sets the motor full-load current the breaker protects — size it to the motor nameplate FLA, not the supply capacity. The Class 10 trip curve means the thermal overload releases within 10 seconds at 7.2× rated current, which is standard for standard induction motor starting (avoids nuisance tripping on start-up inrush). The 100 kA breaking capacity at 400 V AC (and also at 240 V and 500 V) means this breaker can safely interrupt fault currents up to that level without upstream devices needing to clear the fault — critical for high-SCCR panel designs. Phase failure detection is built in, so the breaker trips on loss of one phase, protecting the motor from single-phasing damage.
Integration & Mounting
Mounts on a 35 mm DIN rail per DIN EN 50022 — screw or snap-on fastening. The 45 mm width and 97 mm height fit a standard modular enclosure grid; depth is 96 mm, so account for that behind the panel door. Screw terminals on both main and auxiliary circuits: solid conductors 2× (0.5…1.5 mm²) and 2× (0.75…2.5 mm²); stranded 2× (1…2.5 mm²) and 2× (2.5…6 mm²). AWG for main contacts: 2× (14…10). The auxiliary switch is transverse design and field-addable. Operating frequency in AC-3 duty is 15 cycles per hour maximum — fine for intermittent motor starts, not for continuous jogging.