The Siemens SIRIUS 3RA2150-4UA35-0AP0 is a direct (on-line) starter combining a contactor and thermal overload relay in one enclosure, sized S2 for motor loads up to 40 A in AC-3 duty at 400 V.
Mounts via screw or snap-on to two 35 mm DIN rails; the 274 mm height and 55 mm width fit a standard panel layout with 150 mm depth allowance. Clearance requirements: 50 mm upwards, 32 mm forwards, 10 mm at the side, 10 mm downwards — no extra space needed behind the rail. The screw-type main circuit terminals accept the supplied contactor 3RT2035-1AP00 and link module 3RA2931-1AA00, so the starter arrives as a pre-assembled unit ready for wiring.
Rated 40 A at AC-3 (motor switching) at 400 V, with a maximum operating voltage of 690 V. The AC-3e rating matches the same 40 A at 400 V — this is the enhanced motor-switching category per IEC 60947-4-1, covering frequent starts and plugging. The thermal bimetallic overload release compensates for ambient temperature from -20 to +60 °C, so the trip point stays accurate across the panel's operating range.