What It Is and What It Does
The Siemens SIRIUS 3RT1036-1BF40 is a Size S2 power contactor rated for motor switching. It handles 30 kW at 500 V under AC-3 duty (starting squirrel-cage motors, breaking under load) and delivers 41 A at 400 V under AC-4 duty (plugging, inching, reversing — the tougher switching class that wears contacts faster). The 30 kW AC-3 figure at 500 V is the one that decides fit for most motor circuits — it tells you the contactor can start and stop a motor of that power rating repeatedly. The AC-4 rating of 41 A at 400 V matters if your application reverses or jogs the motor under load, which generates more arcing.
Mounting and Integration
Fastens with screws or snaps onto 35 mm DIN rail per DIN EN 50022. Side-by-side mounting is allowed, which saves panel width when ganging multiple contactors for multi-motor groups. Dimensions are 55 mm wide, 112 mm high, 130 mm deep — a compact S2 footprint that fits standard control panel gland plates and wireways. Main circuit terminals are screw-type, accepting solid wire up to 2x 4 mm² and stranded up to 2x 25 mm². The larger stranded capacity (25 mm²) covers the heavier feeds for the 30 kW motor circuit.
Environmental and Compliance
Operates from -25 °C to +60 °C, stores from -55 °C to +80 °C — wide enough for unheated plant floors or outdoor cabinets in moderate climates. Pollution degree 3 means it's suited for industrial environments with conductive dust or moisture. Front of the contactor carries IP20 finger-safe protection; the terminal area is IP00, so the wiring zone needs enclosure protection in dirty or wet locations.
Switching Performance and Coil Data
Coil operates at 110 V. Pickup and dropout times are 20 to 25 ms DC. Arcing time runs 10 to 15 ms. Mechanical life is 10 million operating cycles typical — that's the contactor structure itself, not the contacts under load. Electrical life depends on the switching category and load current; the AC-3 maximum rate of 800 operations per hour gives a sense of the thermal duty cycle.