SIRIUS S3 power contactor for motor loads
The Siemens 3RT1046-3BD40 is a SIRIUS power contactor in frame size S3, rated for switching three-phase motors up to 55 kW at 400 V in AC-3 duty (cage-rotor motors, normal starting). At 400 V AC-2 it handles 45 kW for slip-ring motors, and the AC-4 rating of 80 A covers plugging and inching applications where the contactor breaks stalled-rotor current.
Termination and environmental ratings
Main circuit connections use screw-type terminals accepting 2x (0.25 to 2.5 mm²) solid or 2x (10 to 50 mm²) stranded conductors, with an additional option for 2x (2.5 to 16 mm²) solid or stranded. The enclosure carries IP20 on the front with the cover or box terminal fitted; the terminal area itself is rated IP00, meaning the panel must provide the final touch-protection barrier. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C, and the unit is rated for pollution degree 3 — suitable for industrial environments with conductive dust or condensation.
Coil and auxiliary contact data
The coil operates at 24 V DC with a pick-up current of 10 A at rated value, dropping to 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — these are inrush values for the DC coil, not steady-state hold. Arcing time spans 10 to 20 ms at DC, and the contactor is rated for 10 million typical mechanical operations.