What It Is and Where It Lands
The Siemens 3RT1034-1DB44 is a SIRIUS 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, so it drops into a standard panel layout without adapter plates. The coil pulls 24 VDC nominal, and the main circuit uses screw-type terminals — expect to land stranded conductors up to 25 mm² or solid up to 16 mm². The front face carries IP20 protection; the terminal area is IP00, meaning the wiring zone expects enclosure protection from the cabinet.
What the Ratings Mean for Your Load
Rated for AC-3 duty at 400 V delivering 15 kW — that is the standard motor-switching category for squirrel-cage induction motors, so this contactor handles a 15 kW motor on a 400 V line. At 500 V the same motor load capability rises to 18.5 kW; at 690 V it drops to 10 kW, reflecting the voltage derate on the switching arc. For reversing or inching duty (AC-4), the contactor is rated 29 A at 400 V. That is the current it can break under the severe switching conditions of plugging or jogging, where the motor is reconnected while still spinning. The AC-4 switching frequency maxes at 250 operations per hour, compared to 1 000 per hour for AC-3 — a direct limit on how fast you can cycle in demanding applications. Auxiliary contacts are rated across the control voltage range: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V. These are the make/break capacities for the control circuit — interposing relays, PLC inputs, or indicator lamps — and they decline with voltage as the arc energy grows.
Integration and Environment
The S2 frame occupies 55 mm width on the DIN rail, with a depth of 179 mm and height of 112 mm. Side-by-side mounting is permitted, so you can gang multiple contactors without spacing — useful for grouping motor starters in a compact MCC section. Rated for pollution degree 3, meaning it tolerates conductive dust or intermittent condensation typical of industrial enclosures. Operating temperature spans -25 to +60 °C; storage range is -55 to +80 °C. The mechanical service life is listed at 10 million operations typical — that is the wear life of the mechanism, not the electrical life under load.