24 V AC coil for SIRIUS size S3 contactors
The 3RT5945-5AC21: Rated at 24 V AC, it matches the standard control voltage common across European and North American panel designs, so it drops into an existing 24 VAC control transformer bus without a separate supply.
Sourcing and compliance
The part carries the SIRIUS brand and is specified for use with Siemens contactors in the size S3 frame — confirm the contactor order code mates with this coil before committing the BOM line.