The Siemens SIRIUS 3RT1924-5AN21 is a Size S0 magnet coil for contactors, rated 220 V AC at both 50 Hz and 60 Hz. It operates across 0.8 to 1.1 times the rated voltage, meaning the coil picks up reliably from about 176 V and holds in up to 242 V — the standard tolerance band for AC-operated contactor coils in this class. This is the replacement coil for any SIRIUS S0 contactor that uses a 220 V AC 50/60 Hz coil assembly, not the contactor itself.
What it fits and how it mounts
The coil is the Size S0 form factor, meaning it swaps directly into any SIRIUS 3RT1 or 3RT2 contactor of the same frame size that uses a screw-terminal coil connection. No rewiring of the panel is needed if the existing contactor is a Size S0 unit — the coil slides onto the magnet stack and the screw terminals accept the same control wiring. The contactor itself snap-mounts onto a 35 mm DIN rail per EN 50022.