SIRIUS S2 power contactor, 48 VDC coil
The Siemens 3RT1036-3BW44 is a SIRIUS S2-size power contactor with a 48 VDC coil, designed for switching motor loads in industrial control panels. It mounts via screw and snap-on onto 35 mm DIN rail per EN 50022, and the front face carries IP20 protection for safe panel integration. Rated at 30 kW at 500 V in AC-3 duty, this contactor handles standard three-phase induction motors up to that power level. For demanding reversing or inching applications, the AC-4 rating at 400 V is 41 A — the figure that governs contactor life under frequent plugging or jogging. Coil holds at 48 VDC nominal. DC switching capability is specified across multiple voltages: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. The operating time on DC is 20 to 25 ms, with an arcing time of 10 to 15 ms. Mechanical life is rated at 10,000,000 operating cycles typical. Maximum switching rates vary by duty: 1,000 cycles/hour at AC-1, 800 at AC-3, and 300 at AC-4. The contactor is rated for side-by-side mounting without derating, and the operating temperature range is -25 to +60 °C.
Termination and wiring
Main current circuit terminals are screw-type, accepting solid conductors 2x (0.25 to 2.5 mm²) and stranded conductors 2x (0.75 to 25 mm²). A second stranded range is listed as 2x (0.75 to 16 mm²). At 40 °C, the minimum permissible conductor size is 16 mm². The contactor footprint is 55 mm wide, 112 mm high, and 179 mm deep. Pollution degree 3 (industrial environment) applies. Storage temperature range is -55 to +80 °C.