What this part is and what it does
The Siemens SIRIUS 3RT1945-5AK61 is a magnet coil designed for Size S3 contactors in the SIRIUS family. It provides the electromagnetic actuation for the contactor main poles and auxiliary contacts, rated for 110 V AC at 50 Hz or 120 V at 60 Hz, with a screw terminal connection.
Lifecycle and sourcing reality
The lifecycle stage for this order code is listed as current, but the description flags it as a phased-out product. The official successor is the SIRIUS 3RT2 series. For a BOM line that needs this exact voltage and Size S3 footprint, the 3RT1945-5AK61 is sourced to order against an RFQ through independent distribution — availability and current pricing are confirmed at quote time.
Deployment context
This coil mounts onto the SIRIUS Size S3 contactor frame, which itself snaps onto a 35 mm DIN rail per EN 50022. The screw terminals accept solid or stranded copper up to 2.5 mm², matching standard panel wiring practice for motor control centers and distribution panels.