What It Is and Where It Fits
The Siemens 3RT1034-3AP04 is a SIRIUS power contactor in size S2, designed for switching motor loads in industrial control panels. It is rated for 15 kW in AC-2 duty at 400 V, which covers wound-rotor motor applications, and 29 A in AC-4 duty at 400 V for plugging and inching of squirrel-cage motors. The contactor mounts on a 35 mm DIN rail per DIN EN 50022, with screw and snap-on fastening, and accepts screw-type terminals for the main current circuit. The front face carries an IP20 degree of protection, while the terminals are rated IP00, meaning the wiring area is exposed and requires enclosure-level protection. Pollution degree 3 rating suits it for industrial environments with conductive pollution.
Key Ratings and What They Mean for the Buyer
The AC-2 rating of 15 kW at 400 V is the headline figure for this contactor — it defines the maximum motor load it can switch under starting and running conditions for slip-ring motors. The AC-4 rating of 29 A at 400 V covers the more severe duty of reversing or inching, where the contactor makes and breaks stalled rotor current. These are the ratings that govern real-world fit, not a generic thermal current. Mechanical life is rated at 10,000,000 operations typical, with maximum switching frequencies varying by duty: 1,200 cycles per hour at AC-1, 750 at AC-2, 1,000 at AC-3, and 250 at AC-4. The AC-4 figure is the one to watch for high-duty-cycle reversing applications. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. The contactor can be mounted side-by-side without derating, which simplifies panel layout.
Termination and Wiring
Main circuit terminals accept solid conductors from 2x 0.25 to 2.5 mm² and stranded conductors from 2x 0.75 to 25 mm². The minimum permissible conductor cross-section at 40 °C is 16 mm². Auxiliary and control circuit wiring uses the same screw-clamp technology. Dimensions are 55 mm wide, 112 mm high, and 164 mm deep — the depth is the dimension that extends behind the DIN rail, so verify cabinet depth clearance before specifying.
Lifecycle and Sourcing Reality
RoHS compliance is confirmed with a substance prohibition date of 05/01/2012, covering the EU RoHS directive. No other compliance documents (UL, CSA, CE) are listed in the spec record, but the SIRIUS family typically carries these; verify the specific nameplate marking for your jurisdiction.