The Siemens 3RT1446-1AH00 is a SIRIUS S3 power contactor — the core switching element for motor loads in a control panel. Rated at 50 kW at 400 V AC-3 (and 148 kW at 690 V AC-3), it handles the heavy lifting on pumps, compressors, and conveyors. The 1,000 V rated insulation voltage gives headroom for 690 V distribution systems without derating the main circuit. Mounts on 35 mm or 75 mm DIN rail — screw and snap-on both work. At 70 mm wide per contactor, it's a standard S3 footprint; plan for that width when laying out the enclosure backplate.
Main power terminals are screw-type, accepting 2x (10…50 mm²) stranded copper — that's good for the full current rating without needing a lug adaptor. Control wiring lands on the front: solid or stranded 0.5…4 mm², two wires per clamp. Strip length and torque are standard for the SIRIUS family; no special tooling required. IP20 on the front with the supplied cover/box terminal keeps fingers out during commissioning. The terminal body itself is IP00, so the panel enclosure must provide the overall IP rating.
Coil and Switching Performance
Coil operates at 50 Hz, 48 V rated value. Pickup time at AC is 10…25 ms; arcing time runs 10…15 ms. That's fast enough for most motor starting sequences — the contactor closes before the inrush current peaks. At 24 V DC the coil draws 10 A, so verify your control transformer sizing if you're running a bank of these. At AC-1 maximum 650 operations per hour, it's comfortable in continuous process duty.