The Siemens 3RA6120-1AP33 is a SIRIUS compact starter — a direct starter that combines a contactor and overload relay in a single 45 mm wide housing. The coil accepts 110-240 V AC/DC (50/60 Hz), so it works across common control voltages without needing a separate coil variant. Trip class is adjustable between Class 10 and Class 20, letting you match the overload curve to the motor start profile — Class 10 for shorter acceleration times, Class 20 for high-inertia loads like fans or conveyors.
The 45 mm width fits a single slot, and the 170 mm height and 165 mm depth leave room for wiring above and below in a typical 200 mm deep enclosure. The main circuit connects via plug-in terminals (no screw terminals on the power side), which speeds replacement. Solid wire from 0.5 to 4 mm² is accepted, with a second conductor from 0.5 to 2.5 mm² — enough for most motor branch circuits up to the rated current.