What It Is and Where It Fits
The Siemens 3RT1034-1BN40 is a SIRIUS-brand power contactor in the S2 frame size, designed for switching motor loads in industrial control panels. It mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 50022, and its 55 mm width and 112 mm height fit standard panel layouts. The 130 mm depth leaves clearance for wiring ducts or adjacent components.
What the Ratings Mean for Your Motor Load
The headline motor ratings are 18.5 kW at 500 V and 10 kW at 690 V under AC-3 duty — that is the category for starting squirrel-cage motors and disconnecting them while running, which covers most conveyor, pump, and fan applications. For AC-2 duty (slip-ring motors, moderate overloads) it is rated 15 kW at 400 V. For AC-4 (plugging, inching, reversing) it handles 29 A at 400 V — a tougher thermal cycle, so the switching frequency drops to 250 operations per hour versus 1 000 for AC-3. The auxiliary contact ratings cover a range of control voltages: 10 A at 24 V DC, 6 A at 230 V AC, and 0.3 A at 220 V DC — enough for PLC inputs or relay coils in the control circuit. The main power terminals accept screw-type connections, with solid wire up to 2x 4 mm² and stranded up to 2x 25 mm², so it handles common motor feeder sizes without adapters.
Environmental Fit and Compliance
Rated for operation from -25 °C to +60 °C, with storage down to -55 °C. Pollution degree 3 means it tolerates conductive dust and condensation typical of factory floors. The front face carries IP20 finger protection; the terminals are IP00, so the contactor expects enclosure protection around the wiring zone. RoHS compliance is documented with a substance prohibition date of 05/01/2012.