The Siemens 3RT5944-5BF41 is a SIRIUS magnet coil, 110 V DC rated, for size S3 contactors with screw-type connections. It replaces a failed coil on a SIRIUS S3 power contactor without removing the contactor from the DIN rail.
What the 110 V DC rating means for fit
The coil is wound for a 110 V DC control supply. That's a common voltage in industrial DC control buses, but it is specific — if your panel runs 24 V DC or 48 V DC control, this coil will not pull in reliably. The holding power at DC is 15 W (typical for the S3 frame), so the control transformer or power supply feeding it needs to deliver that inrush without dropping below the dropout threshold.
Lifecycle and sourcing posture
The lifecycle stage is listed as current. That means Siemens has not flagged this order code for phase-out or last-time-buy as of the latest data. It remains available through the standard SIRIUS distribution channel. For BOM-line planning or urgent line-down replacement, the 3RT5944-5BF41 is sourced and quoted to order against an RFQ — availability and current pricing confirmed at quote time.
Panel integration — size S3 footprint
This coil mounts onto any SIRIUS size S3 contactor frame. The screw terminals accept 2x (2.5... 16 mm²) solid or stranded wire.