What It Is and Where It Fits
The Siemens 3RT1035-1AT60 is a SIRIUS power contactor in the Size S2 frame, designed for switching motor loads in industrial control panels. It mounts on a 35 mm DIN rail per EN 50022, with a 55 mm width that fits standard panel layouts. Rated for AC-2 duty at 18.5 kW at 400 V, this contactor handles wound-rotor motors and slip-ring applications where moderate inrush and frequent switching are the norm. The AC-4 rating of 35 A at 400 V covers plugging and inching duty for reversing or jogging loads.
Key Ratings and What They Mean
The AC-2 rating of 18.5 kW at 400 V is the headline motor-switching figure — it tells you the contactor can handle the starting and running currents of a wound-rotor motor up to that power without exceeding thermal limits. For comparison, the AC-3 rating (squirrel-cage motors) would typically be higher, but this unit's AC-2 spec is the one that governs fit for slip-ring or crane-duty applications. The AC-4 rating of 35 A at 400 V is the reversing/plugging limit — if your application requires frequent reversal or inching, this is the number that matters. Exceeding it risks contact welding or accelerated wear. Mechanical life is rated at 10 million cycles typical, which is standard for a SIRIUS Size S2 contactor and gives a solid baseline for maintenance planning in high-cycle applications like conveyors or packaging lines.
Mounting and Integration
Snap-on mounting onto a 35 mm DIN rail per DIN EN 50022 is standard, with screw-type terminals for the main current circuit. The front face carries an IP20 rating, meaning finger-safe when installed in an enclosure; the terminal area is IP00, so live parts are exposed during wiring — standard practice for panel builders. Side-by-side mounting is permitted without derating for most applications, which helps when packing multiple contactors into a tight panel. The 55 mm width per unit means a row of four fits in a standard 220 mm wide enclosure section. Wire sizes: solid conductors accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) up to 2x (0.75 to 4 mm²) maximum. Stranded conductors handle 2x (0.75 to 25 mm²). The minimum permissible cross-section at 40 °C is 16 mm² for the main circuit.
Environmental and Compliance
Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. Pollution degree 3 means it's suitable for industrial environments with conductive dust or occasional condensation — typical for most factory floor installations. RoHS compliance date is 05/01/2012, meaning the contactor meets EU substance restrictions for lead, mercury, cadmium, and other restricted materials as of that date. This is the standard RoHS declaration for Siemens SIRIUS products of this generation.