The Siemens 3RT1945-5AV61 is a SIRIUS magnet coil for Size S3 contactors, rated 480 V AC at 60 Hz with screw terminals. It is the replacement coil for legacy 3RT1 contactor frames — if you have a 3RT1 Size S3 contactor in a panel and the coil fails, this is the direct spare.
What the rating means for fit
The 480 V AC 60 Hz coil voltage is the control voltage that picks up and holds the contactor. If your panel supplies 480 V AC at 60 Hz to the coil circuit, this coil matches. The screw terminal connection is standard for Size S3 contactor bases — no special tooling needed. Mounts directly onto the contactor's magnet system; no adapter required.