SIRIUS coupling contactor, S3 frame, 24 VDC coil
The Siemens SIRIUS 3RT2046-1KB40-1AA0 is a coupling contactor in the S3 frame size, designed for switching auxiliary and control circuits rather than main motor loads. It carries a 24 VDC coil with a peak inrush of 2.7 A, and the coil termination uses screw-type terminals. The contactor mounts via screw and snap-on onto a 35 mm standard mounting rail per DIN EN 60715, and is approved for standing installation on a horizontal mounting surface only. The envelope measures 70 mm wide by 140 mm tall by 152 mm deep, with a 10 mm clearance required at the side and 10 mm upward and downward for arc containment. Wire range accepts solid conductors from 2.5 to 16 mm² and stranded from 6 to 70 mm², with a dual-wire capability of 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) for auxiliary connections.
Switching frequency and duty-cycle ratings
Maximum switching frequency varies by duty class: 900 operations per hour at AC-1 (resistive), 850 at AC-3 and AC-3e (motor starting), 350 at AC-2 (slip-ring motor), and 250 at AC-4 (plugging/inching). The arcing time is 10 to 20 ms, and the DC operating time is 38 to 57 ms. Auxiliary contact ratings are voltage-dependent: 10 A at 24 V, 2 A at 48 V or 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V. The contactor includes an auxiliary switch as standard.
Environmental limits and mechanical endurance
Operating temperature range is -25 to +60 °C; storage range extends from -55 to +80 °C. Mechanical life of the contactor is rated at 10 million typical operations. Vibration resistance is specified at 9.8 g for 5 ms and 5.6 g for 10 ms under AC conditions.