What it is and what it does
The Siemens 3RT1035-1BD40 is a SIRIUS power contactor in the S2 frame size, designed for switching motor loads and resistive loads in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 50022 via screw and snap-on fastening, and connects via screw-type terminals on the main current circuit. The key motor rating is 22 kW at 500 V under AC-3 duty, and 11.4 kW at 690 V under AC-3 duty — these are the numbers that govern fit for a motor starter or reversing contactor pair. For resistive loads (AC-1), the switching rate reaches 1,200 operations per hour; for AC-3 motor starts, 1,000 ops/h; for AC-4 inching/jogging, 300 ops/h. DC switching capability is covered by DC-13 ratings: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. The contactor's mechanical life is rated at 10 million operations typical, and the dropout time on DC control is 20 to 25 ms with an arcing time of 10 to 15 ms.
Mounting and integration
The 3RT1035-1BD40 occupies a 55 mm wide by 112 mm high by 130 mm deep footprint on the DIN rail. Side-by-side mounting is permitted, so multiple contactors can be ganged without spacing gaps — useful for compact reversing or star-delta assemblies. The front face carries an IP20 rating; the terminal area is IP00, so it expects enclosure protection for the wiring zone. Wire sizing: the main circuit accepts stranded conductors from 2x (0.75... 25 mm²) and solid or stranded from 2x (0.75... 16 mm²). The control circuit takes solid wire 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²), up to max 2x (0.75... 4 mm²). At 40 °C the minimum permissible conductor is 16 mm².
Environmental and compliance
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Pollution degree 3 means it's suited for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation. The substance prohibition date of 05/01/2012 aligns with RoHS compliance requirements.