The Siemens 3RT1934-5AP61 is a SIRIUS magnet coil designed for Size S2 contactors, accepting 220 V AC at 50 Hz or 240 V AC at 60 Hz via screw terminals. It's the control-side component that pulls in the contactor armature — no coil, no switching. This is a phased-out product; the official successor is the SIRIUS 3RT2 series.
The coil operates on AC control voltage only — 220 V at 50 Hz, 240 V at 60 Hz. The voltage tolerance band is 0.8 to 1.1 times the rated value, so the coil holds in reliably down to about 176 V AC and picks up cleanly up to 264 V AC. That's a standard margin for industrial control transformers with typical line sag. The screw terminals match the Size S2 contactor base; no adapter needed for the existing wiring.