SIRIUS Size S3 Power Contactor, 24 VDC Coil
The Siemens 3RT1446-6BB46-ZM96 is a SIRIUS power contactor in the Size S3 frame, designed for switching motor loads in industrial control panels. It carries a 24 VDC coil and is rated for 29.9 kW at 500 V and 38.2 kW at 690 V, making it a fit for medium-horsepower three-phase motors in conveyor, pump, and fan applications. The contactor mounts via screw and snap-on onto 35 mm or 75 mm standard DIN rail, with side-by-side mounting permitted for dense panel layouts. Rated insulation voltage is 1 000 V, with a pollution degree of 3, so it's suited for industrial environments where conductive dust or condensation is present. The operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. Mechanical life is rated at 10 000 000 cycles typical, and the maximum switching rate at AC-1 is 650 operations per hour.
Termination and Wiring
Both the main current circuit and the auxiliary/control circuit use screw-type terminals. The main contacts accept solid conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and up to 2x (0.75 to 4 mm²). For AWG cables, the range is 7 to 1/0. Minimum permissible conductor sizes are 50 mm² at 40 °C and 35 mm² at 60 °C — derate for higher ambient temperatures.
Switching Performance and Duty Ratings
For AC motor duty at 400 V, the contactor is rated 22 kW in AC-2 (slip-ring motor starting). At 230 V and 60 °C ambient, it handles 50 kW; at 690 V and 60 °C, it handles 148 kW — note these are at elevated temperature, so the coil hold and contact life are derated accordingly. For DC switching, the contactor is rated 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. Arcing time is 10 to 15 ms at AC, and 14 to 20 ms at DC.