Motor Protection Circuit Breaker — SIRIUS 3RV2021-4AA10-ZX95
The breaker includes phase failure detection, so a lost phase on a three-phase line will trip the load before single-phasing damages the winding. Breaking capacity is 25 kA at 400 V and 100 kA at 240 V, which covers most industrial panel fault-current levels downstream of a distribution transformer. The interrupting ratings at higher voltages are lower — 5 kA at 500 V and 2 kA at 690 V — so verify the available fault current at the point of installation if you're running a 690 V line. The 45 mm width (three module spaces) is standard for SIRIUS breakers in this frame size.
Integration Notes
Terminals accept 2×(1…2.5 mm²) or 2×(2.5…10 mm²) solid or stranded copper — screw-type main contacts with M4 threads. At AC-3 duty the maximum switching rate is 15 operations per hour — adequate for manual or infrequent motor starts, but not for high-cycling applications like a rapid-reversing conveyor. For higher duty cycles, consider a contactor paired with a smaller thermal overload.