What this SIRIUS S2 power contactor is and what it does
The Siemens 3RT1034-1BD40 is a SIRIUS-brand power contactor in the S2 frame size, rated for motor switching duty. It handles AC-3 loads up to 1000 operations per hour, delivering 18.5 kW at 500 V and 10 kW at 690 V. That AC-3 rating is the one that matters for squirrel-cage motor starting — the contactor makes and breaks the stalled-rotor current every cycle, so the 1000 ops/h ceiling tells you it can keep up with a fast-cycling conveyor or pump station without derating. Screw-type terminals on the main circuit accept stranded wire up to 2x 25 mm² and solid up to 2x 4 mm². The contactor mounts on a 35 mm DIN rail per EN 50022 via screw and snap-on fastening, and side-by-side mounting is allowed — no gap needed between units on the rail. Mechanical life is rated at 10 million operations typical. That figure governs the contactor's wear-out interval in high-cycle applications like stamping presses or packaging lines — plan spares around it, not the electrical endurance.
Where it fits — panel and environment
The 55 mm width and 112 mm height fit standard DIN-rail enclosures. Depth is 130 mm, which clears most 200 mm deep cabinets with room for wiring ducts. Pollution degree 3 rating means it's suited for industrial environments with conductive dust or occasional condensation — no conformal coating required for typical panel duty. Front of the contactor carries IP20 finger-safe protection; the terminal area is IP00, so live parts are exposed below the front cover. Operating temperature range is -25 to +60 °C, storage -55 to +80 °C. For high-ambient panels near ovens or foundry lines, the +60 °C ceiling is the limit — above that, derate per the thermal curve.
Switching performance and coil data
Arcing time is 10 to 15 ms at DC, and the contactor's DC switching capability is specified by voltage: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V. These are the make-and-break ratings for DC loads — inductive loads like DC brake coils or solenoid valves need the lower end of the curve. AC switching frequencies: AC-1 resistive loads up to 1200 ops/h, AC-2 slip-ring motors at 750 ops/h, AC-3 squirrel-cage at 1000 ops/h, AC-4 plugging/inching at 250 ops/h. The AC-4 figure is the one to watch for reversing or jogging duty — it's a quarter of the AC-3 rate because each operation is harder on the contacts. At 400 V, the contactor is rated 15 kW in AC-2 and 29 A in AC-4. The AC-2 rating applies to wound-rotor motors where the starting current is lower; AC-4 covers the full locked-rotor current during reversing.
Lifecycle and compliance
RoHS compliance date is May 1, 2012, covering the EU RoHS directive. The contactor carries no built-in auxiliary contacts or surge suppression — those are ordered separately as add-on blocks.