The Siemens SIRIUS 3RT1945-5AD22 is a magnet coil for Size S3 contactors, rated 42 V AC at both 50 Hz and 60 Hz. It uses spring-loaded connection technology for the control wiring — no screw terminals on the coil, so the panel wireman needs a small flat-blade screwdriver to depress the cage clamp.
The coil mounts directly onto the SIRIUS Size S3 contactor armature; no additional bracket or adapter is needed. The 42 V AC control supply is common in older European panel designs — confirm the control transformer taps before fitting.