The Siemens SIRIUS 3RT1044-3AF04-ZW95 is an S3-frame power contactor rated for motor switching at 30 kW under AC-2 duty at 400 V. That AC-2 rating means it's designed for slip-ring motors or wound-rotor applications where the contactor opens under moderate inrush — a step above general AC-3 for compressor or conveyor starts.
For AC-4 duty (plugging or inching), it handles 55 A at 400 V — useful if your line requires frequent reversing. The contactor also carries a 37 kW rating at 500 V and 18.6 kW at 690 V, giving headroom for 480 V or 575 V systems common in North American plants.
Wiring and Integration Details
Main circuit terminals are screw-type, accepting 2x (10 to 50 mm²) stranded or 2x (0.25 to 2.5 mm²) solid. That's a wide range — fine for 16 mm² motor feeds, but the smaller solid wire suits control-circuit looping.