Size S2 power contactor for motor loads up to 22 kW at 500 V
The Siemens SIRIUS 3RT1035-1AR60 is a Size S2 power contactor designed for switching three-phase motors and resistive loads in industrial control panels. Its main circuit is rated at 400 V 50 Hz, delivering 18.5 kW at AC-2 duty and 22 kW at 500 V. At 690 V it handles 11.4 kW, giving you the headroom for a 400 V motor with a healthy voltage drop margin. The contactor mounts via screw and snap-on onto 35 mm DIN rail per EN 50022, and side-by-side mounting is permitted — no derating gaps required between units in a row, which simplifies panel layout. Screw-type terminals on the main circuit accept stranded conductors up to 2x 25 mm², and the auxiliary circuit accepts solid wire up to 2x 4 mm². That covers the typical motor feeder cable range up to 16 mm² without needing adaptor lugs.
Switching frequency and thermal limits for continuous duty
Maximum switching frequency depends on duty class: 1200 operations per hour at AC-1 (resistive), 1000 at AC-3 (motor start/run), and 600 at AC-2 (slip-ring motor). At AC-4 (plugging/inching) the limit drops to 300 ops/h. These are the thermal limits of the contactor — exceeding them will overheat the coil and arc chamber. Operating ambient temperature range is -25 to +60 °C, with storage from -55 to +80 °C. Pollution degree 3 means it's rated for industrial environments with conductive dust or humidity — no conformal coating needed for most panel interiors. Mechanical endurance is 10 million operations typical, which for a contactor in a conveyor or pump start/stop cycle at 1000 ops/h translates to roughly 10,000 hours of service before contact wear becomes a consideration.
Auxiliary contact ratings for control circuit integration
The built-in auxiliary contacts are rated at 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. At 110 V they carry 1 A, and at 220 V only 0.3 A — so if you're feeding a 220 V PLC input from these contacts, check the load current against the 0.3 A limit. Coil operating range spans 0.8 to 1.1 times rated voltage at 50 Hz, and 0.85 to 1.1 at 60 Hz. Operating time is 7 to 20 ms AC, with arcing time between 10 and 15 ms. That's fast enough for most motor start sequences but not for high-speed inching — use a dedicated DC coil contactor for that.
Panel integration and wiring constraints
Dimensions are 112 mm high, 55 mm wide, 115 mm deep — the S2 frame occupies about 6.2 cm² of DIN rail footprint. At 55 mm wide, four units fit in a 220 mm wide enclosure section with room for a 10 mm end bracket. IP20 on the front, IP00 at the terminals — the terminal area is not touch-safe until the enclosure door is closed. In a panel with IP54 rating, this contactor is fine; in an open cabinet, install finger guards over the screw terminals. Wire range on the main circuit: stranded 2x 0.75 to 25 mm², solid or stranded 2x 0.75 to 16 mm². The auxiliary circuit accepts solid 2x 0.5 to 4 mm². Use ferrules on stranded wire for reliable termination in the screw clamp.