What it is and what it does
The Siemens 3RT1046-1BE44 is a SIRIUS power contactor in size S3, designed for switching motor loads and resistive loads in industrial control panels. Its AC-2 rating of 45 kW at 400 V makes it a fit for slip-ring motor duty, while the AC-4 rating of 80 A at 400 V covers reversing and inching applications where the contactor breaks full motor current. The screw-type terminals on the main circuit accept stranded conductors up to 2x 50 mm², which is enough for the full rated current without parallel runs.
Mounting and integration
Mounts via screw or snap-on onto 35 mm or 75 mm standard mounting rail, so it drops into any DIN-rail enclosure without drilling. The 70 mm width and 146 mm height fit the S3 footprint; depth is 201 mm, which matters when the gland plate is tight. Side-by-side mounting is allowed, so you can gang multiple contactors without a gap — just watch the thermal derating if you pack them tight. IP20 on the front with the cover or box terminal installed; the terminal itself is IP00, so the panel door or an additional cover handles touch protection.