SIRIUS S3 power contactor — 55 kW at 500 V AC-3
The Siemens SIRIUS 3RT1046-1XB40-0LA2 is a Size S3 power contactor rated for motor switching up to 55 kW at 500 V in AC-3 duty, and 25.4 kW at 690 V. The 24 VDC coil draws 10 A at pickup, holding at the rated value. Screw-type terminals on the main circuit accept up to 50 mm² stranded cable. The contactor mounts via screw or snap-on onto 35 mm or 75 mm standard DIN rail, with side-by-side mounting permitted for multi-contactor assemblies.
Duty cycles and thermal limits
Maximum switching rates: 900 operations/hour in AC-1 (resistive), 850 ops/h in AC-3 (motor), 350 in AC-2, and 250 in AC-4 (plugging/inching). Mechanical life is 10 million operations typical. Ambient operating range spans –40 to +70 °C; storage from –55 to +80 °C. Arcing time is 10–15 ms; the DC dropout delay is 14–20 ms.
Mounting and clearances
Dimensions: 176 mm height, 70 mm width, 152 mm depth. Minimum clearance for ventilation: 10 mm upwards, 10 mm downwards, 10 mm at the side, and 20 mm forwards. Solid wire sizes accepted: 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), max 2x (0.75–4 mm²). Stranded: 2x (10–50 mm²) for the main circuit, plus 2x (2.5–16 mm²) for auxiliary circuits.