What This SIRIUS S2 Contactor Does
The Siemens 3RT1034-3BM40 is a SIRIUS-branded power contactor in the S2 frame size, designed for switching motor loads and resistive loads in industrial control panels. Its AC-3 rating of 18.5 kW at 500 V means it handles standard squirrel-cage motors up to that power, and the 29 A AC-4 rating at 400 V covers reversing or inching duty where the contacts break full load current. The screw-type terminals on the main circuit accept stranded wire up to 25 mm², sized for the currents this contactor handles. It mounts on a 35 mm DIN rail per EN 50022, either snapped on or screwed down, and fits a 55 mm wide slot in the enclosure. The IP20 front keeps fingers out of the live parts, while the IP00 terminal area means it's intended for installation inside a locked cabinet, not out on the plant floor.
Key Ratings and What They Mean for Your Panel
The 18.5 kW motor rating at 500 V is the headline number, but the 10 kW at 690 V rating matters for systems running on higher supply voltages — it's not a simple linear derate, so check your line voltage against that column. The AC-4 rating of 29 A at 400 V is the one to watch if you're doing plugging or jogging; exceed that and the contacts will erode faster than the mechanical life of 10 million operations suggests. Operating temperature range of -25 to +60 °C covers most panel environments, and storage down to -55 °C is fine for unheated warehouses. Pollution degree 3 means it's rated for the conductive dust and humidity you'd see in a typical industrial setting, not a clean room.
Sourcing and Lifecycle Reality
The RoHS compliance date of May 1, 2012, confirms it meets the EU substance restrictions. CE marking is standard for the SIRIUS range, and the DIN rail mount per EN 50022 is a global standard, so it fits panels built to IEC or UL 508A practices.