What it is and what it does
The Siemens 3RT1044-1BE44 is a SIRIUS power contactor in Size S3, designed for switching motor loads in control panels. It carries a 55 A rating at AC-4 400 V — that is the heavy-duty switching category for reversing, inching, and plugging duty where the contactor makes and breaks stalled-rotor currents. For AC-2 duty (slip-ring motors), it is rated at 30 kW at 400 V. The 37 kW rating at 500 V covers standard three-phase induction motors on a 500 V line. Screw-type terminals on the main circuit accept stranded conductors up to 2x 50 mm², which is heavy enough for the full rated current without double-lugging. The contactor mounts on 35 mm or 75 mm standard DIN rail via screw and snap-on fastening, and side-by-side mounting is supported — no derating gap required for multiple units in a row.
Where it fits
Dimensions are 146 mm high, 70 mm wide, and 201 mm deep. The front face carries an IP20 rating with the cover or box terminal installed; the terminal area itself is IP00. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. Pollution degree 3 means it is suited for industrial environments with conductive dust or occasional condensation — no additional conformal coating needed for a typical IP54 or better enclosure.