SIRIUS S3 power contactor — 110 VDC coil, screw terminals
The Siemens SIRIUS 3RT1046-1XF40-0LA2 is an S3 frame power contactor with a 110 VDC coil, built for motor switching and resistive loads in industrial control panels. It mounts via screw fixing or snaps onto standard 35 mm and 75 mm DIN rails, which covers both common panel profiles and the wider rail used in some European enclosures. Rated switching frequency varies sharply by duty: 900 operations per hour at AC-1 (resistive), 850 at AC-3 (squirrel-cage motor start/run), 350 at AC-2 (slip-ring motor), and 250 at AC-4 (plugging/inching). For a conveyor or pump running continuous AC-3 duty, that 850 cycles/hour headroom is generous — the thermal limit on the contactor, not the coil, is what governs here. Motor power ratings reach 55 kW at 500 V and 25.4 kW at 690 V, so it handles European 400 V motors comfortably and steps up to 690 V industrial networks without derating the frame. The operating temperature range of -40 to +70 °C means it lives in unheated plant areas or near process heat without forced cooling.
Panel fit and wiring
Dimensions are 176 mm high, 70 mm wide, 152 mm deep — the S3 frame is a standard footprint across the SIRIUS contactor family. Side-by-side mounting is permitted with zero spacing, which saves rail length in dense panels. Main circuit terminals accept screw-type connections: solid conductors from 0.5 to 4 mm² on the control side, and stranded up to 50 mm² for the power loop. The clamping range covers everything from signal-level wiring to full motor cable cross-sections without adapter lugs. Clearance distances are specified: 10 mm upward, 10 mm downward, 20 mm forward, 10 mm at the sides. These are the minimum air gaps to maintain rated insulation — useful when laying out a row of contactors on a DIN rail to avoid arc tracking.