What This Contactor Is and Where It Fits
The Siemens SIRIUS 3RT1036-3BB40 is a power contactor in the S2 frame size, designed for switching motor loads in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 50022, with screw-and-snap-on fastening, and accepts screw-type terminals for the main current circuit. The 24 VDC coil is rated at 10 A holding current at 24 V, with a DC operating time of 20 to 25 ms and an arcing time of 10 to 15 ms.
Key Ratings and What They Mean for Your Load
The AC-2 rating at 400 V is 22 kW, which covers wound-rotor motor switching — common in crane and hoist applications where slip-ring motors need controlled acceleration. The AC-4 rating at 400 V is 41 A, covering plugging and inching duty for reversing or jogging applications. At 500 V the contactor is rated for 30 kW, and at 690 V for 11.4 kW, so it handles higher-voltage motor circuits but with reduced power due to the voltage derating. The mechanical endurance is 10 million cycles typical, with maximum switching rates of 1000 cycles/hour at AC-1, 800 at AC-3, and 300 at AC-4 — so for high-duty reversing applications, the AC-4 rate governs the lifetime. The contactor is rated for pollution degree 3, meaning it's suitable for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation. The front is IP20 protected (finger-safe), while the terminals are IP00 — so the panel enclosure provides the terminal protection. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C, which covers most indoor industrial conditions.
Wiring and Mounting
The main circuit screw terminals accept 2x (0.75 to 25 mm²) stranded wire or 2x (0.25 to 2.5 mm²) solid wire, with a minimum permissible cross-section of 16 mm² at 40 °C. Side-by-side mounting is allowed without derating, which saves panel width when grouping multiple contactors. The S2 frame measures 55 mm wide, 112 mm high, and 130 mm deep — check your enclosure depth before committing.