The Siemens 3RA1140-4JD44-0BB4 is a SIRIUS non-fused motor starter in size S3, combining a contactor and a thermal bimetallic overload relay in one assembly. It is a direct starter, meaning it connects the motor directly to the line for across-the-line starting — the most common method for fixed-speed induction motors on pumps, fans, and conveyors. Rated for 63 A at 480 V AC-3 (motor switching duty), it handles a 50 hp motor at 460/480 V and delivers 30 000 W at 400 V. The 24 V DC coil is held in by the control voltage; the thermal Class 10 overload protects the motor against sustained overcurrent, tripping fast enough for standard induction motors without nuisance trips on start-up.
Snaps directly onto 60 mm busbar systems — no separate mounting plate needed. Mounting position is vertical only. The supplied busbar adapter (FBS10070) and link module (3RA1941-1BA00) are included; the contactor supplied is a 3RT1044-1BB40. For enclosure planning: the unit is 354 mm high, 70 mm wide, 212 mm deep. Clearance required: 90 mm upward, 12 mm at the side, 10 mm downward, 6 mm backward, 0 mm forward.