The Siemens SIRIUS 3RT1965-5QP31 is a changeover operating mechanism — a magnet coil assembly — designed for the 3RT106 and 3RT146 contactor frames. It provides the mechanical latching function that holds the contactor closed after the coil is energized, then releases it on command or power loss. This dual AC/DC capability simplifies panel wiring — you can feed it from either a control transformer or a DC supply without swapping coils.
Because it is current-production, the normal Siemens distribution channel carries it.
If your control circuit runs at 240 V AC (common in North American panels), this coil is within range — the 277 V AC rating gives headroom above 240 V. For a 208 V AC control bus, the coil still pulls in reliably since the 277 V rating is the maximum, not the minimum. The electronic operating mechanism includes AS-Interface communication and an RLT (Remote Local Trip) signal. That means this coil can be addressed and monitored on an AS-i network — useful if the contactor sits in a distributed I/O zone where you want feedback on the latching state without running separate sense wires back to the PLC.