The Siemens 3RT1034-3BB44-3MA0 is a SIRIUS-brand power contactor in the S2 frame size, rated for motor switching and resistive loads. At 55 mm wide and 112 mm tall, it fits standard panel layouts without crowding adjacent devices. Screw terminals on the main circuit accept 2x (0.75...16 mm²) stranded or 2x (0.25...2.5 mm²) solid — enough for the full rated current without lug adapters.
At 500 V it is rated 18.5 kW; at 690 V it derates to 10 kW. Maximum operating frequency varies by duty: 1 200 cycles/hour at AC-1 (resistive), 1 000 at AC-3, 750 at AC-2, 250 at AC-4. For a conveyor running at 30 starts/hour, any of these is fine; for a press that cycles 600 times/hour, AC-3 is the limit.
RoHS compliance date is 05/01/2012, meaning it meets the EU RoHS directive for substances of concern. The contactor carries a typical mechanical life of 10 million operations — the figure for the contactor body itself, not the contacts under load.