SIRIUS S6 power contactor — panel-fit and switching duty
The Siemens SIRIUS 3RT1056-6NB36-3PA0 is a size S6 power contactor with screw fixing, designed for motor switching in control panels. Its 170 mm depth, 120 mm width, and 172 mm height fit the S6 frame envelope, accepting stranded conductors from 25 to 120 mm² on the main poles. Rated coil voltage spans 21 to 27.3 V, with screw-type terminals on the magnet coil. Opening time is 80 to 90 ms on both AC and DC control, and arcing time runs 10 to 15 ms — figures that matter for coordinating upstream protection and predicting contact wear in high-cycle applications. Mechanical life is rated at 10,000,000 typical operations. Switching frequency varies by duty: 800 operations/hour at AC-1 (resistive loads), 750 ops/h at AC-3 (squirrel-cage motors), and 130 ops/h at AC-4 (plugging/inching). The AC-3 rating is the one that governs most motor-starting applications — the contactor is sized for that curve, not the higher AC-1 figure.
Mounting and wiring constraints
Mounting position allows a vertical surface with +/-90° rotation and +/-22.5° tilt forward/back. Clearance requirements: 10 mm upwards, 10 mm downwards, 20 mm forwards, and 10 mm at the side. The auxiliary switch is included; its rated values are 10 A at 24 V, 2 A at 48 V, 2 A at 60 V, and 1 A at 110 V. Solid and stranded auxiliary wiring accepts 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and max 2x (0.75 to 4 mm²). The main power terminals take stranded 25 to 120 mm². Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.