Compact motor starter — 45 mm footprint, 53 kA SCCR
The Siemens 3RA6120-0CB30 is a SIRIUS compact starter in a direct-starter design, rated 53 kA at 400 V — that's the short-circuit breaking capacity the device can safely interrupt without upstream fuses needing to clear first, which simplifies panel coordination.
Trip class selection and continuous duty
Trip class is adjustable between CLASS 10 and CLASS 20 — a single rotary switch or DIP setting lets you match the overload release to the motor start profile: Class 10 for fast-starting loads like pumps, Class 20 for high-inertia fans or conveyors that need a longer acceleration ramp. Rated for continuous operation per IEC 60947-6-2, meaning it can hold rated current indefinitely without thermal cycling — no need to derate for duty cycle in a normal process line. Power dissipation is 2.8 W AC maximum and 2.9 W DC maximum — low enough that multiple units can be ganged on a DIN rail without forced cooling in a standard IP20 enclosure.
Environmental and mechanical endurance
Shock rated to 60 m/s² (6 g) for 10 ms, three shocks per axis; vibration tested to 20 m/s² at 5.8–500 Hz — this meets the robustness needed for machine-mounted applications where the starter sees conveyor or press impacts. Operating temperature range is -20 to +60 °C, storage and transport from -55 to +80 °C, with pollution degree 3 — suitable for industrial environments with conductive dust or occasional condensation.