What This SIRIUS Size S2 Contactor Does
The Siemens 3RT1035-1AK68-0PA4 is a SIRIUS power contactor in Size S2, designed for switching motor loads in industrial control panels. It's rated for 22 kW at 500 V AC-3 and 18.5 kW at 400 V AC-2, which covers the typical 3-phase induction motor range for pumps, fans, and conveyors on 400 V or 480 V lines. The AC-3 rating is the one that matters for most motor starts — it's the full-load switching current, not just the resistive hold. Mounts on a 35 mm DIN rail per EN 50022, with screw and snap-on fastening. Side-by-side mounting is allowed, so you can pack multiple contactors in a row without a gap — useful when panel width is tight. The front face carries an IP20 rating (finger-safe), while the terminal area is IP00, meaning the wiring zone needs clearance from live parts in the enclosure.
Wiring and Termination Reality
Main circuit terminals are screw-type, accepting solid conductors from 2x (0.5 to 1.5 mm²) up to 2x (0.75 to 4 mm²), and stranded from 2x (0.75 to 25 mm²). That's a wide range — fine for both control wiring (1.5 mm²) and power tails (16 mm² or 25 mm²). The solid-or-stranded entry also lists 2x (0.75 to 16 mm²), which is the practical limit for most panel builders. Strip length and torque values aren't in this record, but the screw terminals are standard for the class. Auxiliary contacts are rated for switching at multiple voltages: 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. That covers PLC-level signals (24 VDC) and control circuits up to 400 VAC. The 10 A at 24 V is useful for direct drive of indicator lamps or small relays without an interposing stage.
Environmental and Mechanical Limits
Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. That's typical for indoor panel environments — no special heating or cooling required unless the enclosure sits in a hot plant area. Pollution degree 3 means it's rated for conductive pollution environments (industrial, not clean-room), so it's fine in most factory-floor panels without conformal coating. Mechanical life is 10 million operations typical. Switching frequency varies by duty: 1200 cycles/hour at AC-1 (resistive), 1000 at AC-3 (motor), and 300 at AC-4 (plugging/inching). For a conveyor running at 30 starts/hour, that's years of service before mechanical wear becomes a factor.