Siemens 3RT1035-1BB40 Contactor

Siemens Sirius 3RT1035-1BB40 is a 3-pole power contactor with a 24 V DC coil, designed for AC-3 duty and rated to switch 40 A on the main circuit. It handles motor-start loads up to 18.5 kW at 400 V in a compact Size S2 frame with screw-terminal connections. The main circuit provides three normally open contacts (NO x3) for straightforward motor control, while the device is specified for front IP20 protection and back IP00 at the terminal side. Operating ambient temperature ranges from -25 to +60 C, enabling reliable performance in typical industrial environments. Mechanical life is specified at up to 10,000,000 switching cycles; with an electronics-compatible auxiliary switch block, life is typically 5,000,000 cycles. This combination of coil voltage, current rating, and AC-3 duty makes the 3RT1035-1BB40 a solid choice for mid-range motor control tasks in automation and machine-building applications.