What this coil is and where it fits
The Siemens SIRIUS 3RT5944-5BM41 is a DC-operated magnet coil for size S3 contactors, rated 220 V DC with a screw-type connection. It is designed as a replacement or spare coil for SIRIUS 3RT power contactors in the S3 frame — the same frame used across the 3RT5044 and 3RT5046 families. The coil itself carries no auxiliary contacts; it simply energises the contactor armature when 220 V DC is applied, so the buyer is sourcing a service part, not a standalone switching device.