What it is and what it does
The Siemens SIRIUS 3RT1046-1BM44 is a size S3 power contactor for switching motor loads in industrial control panels. It is rated for 45 kW at 400 V in AC-2 duty (slip-ring motors, moderate overload) and 80 A in AC-4 duty (reversing, plugging, inching — the hardest motor-switching category). The screw-type main circuit terminals accept stranded conductors up to 2x 50 mm², so it handles the cable sizing for a 45 kW motor on a 400 V line without an external terminal block.
Mounting and panel fit
Snap-on mounting onto 35 mm or 75 mm standard DIN rail — no tools needed for the rail, though the screw terminals need a screwdriver. The 70 mm width and 146 mm height fit a standard S3 contactor footprint; depth is 201 mm including the terminals. Side-by-side mounting is permitted without derating for the thermal ratings listed, which helps when packing multiple contactors into a row on the rail.
Lifecycle and sourcing
The lifecycle stage is listed as current — meaning Siemens still produces this part as an active catalog item. It carries a RoHS compliance date of 05/01/2012, so it meets the EU substance restrictions for new installations. For a BOM line that needs a known, in-production contactor, this one is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time.