What this part is and what it does
The Siemens SIRIUS 3RT1934-5BW41 is a 48 V DC magnet coil for Size S2 contactors, terminated with screw terminals. It is the replaceable coil assembly that energizes the contactor's armature.
What the ratings mean for fit
The coil is rated for 48 V DC — this is the nominal pick-up and hold voltage. The Size S2 designation matches the contactor frame it fits.
Deployment context
This coil is used inside a control panel on a DIN-rail-mounted SIRIUS contactor. The 48 V DC control voltage is less common than 24 V DC, so verify the control transformer or power supply before specifying. The coil's DC rating means it has built-in suppression for the inductive kickback — but for long cable runs, a free-wheeling diode across the coil terminals is still good practice to protect the PLC output driving it.