The Siemens SIRIUS 3RT1944-5AN21 is a replacement magnet coil for Size S3 contactors, wound for 220 V AC at both 50 Hz and 60 Hz. It uses a screw terminal connection for the control supply. This is a phased-out product; the official successor is the SIRIUS 3RT2 series.
Listed as a phased-out product. The manufacturer's designated successor is the SIRIUS 3RT2 series. For BOM lines that require this exact order code, sourcing is through the surplus and broker channel.
This coil is mechanically and electrically sized for SIRIUS Size S3 contactors. The screw terminals accept the same control wiring as the original assembly.