SIRIUS Size S2 power contactor — what the ratings mean for your motor circuit
The Siemens 3RT1036-1AH04 is a SIRIUS Size S2 power contactor, screw-type terminals, designed for switching motor loads in control panels. Its headline motor ratings are 22 kW at AC-2 duty at 400 V (slip-ring motors, moderate switching) and 41 A at AC-4 duty at 400 V (plugging, inching, reversing — the harshest motor-switching regime). The AC-4 figure is the one to watch for reversing or jogging applications; the AC-2 figure governs normal starting and stopping of wound-rotor motors. Mounting is screw and snap-on onto 35 mm standard mounting rail per DIN EN 50022, with side-by-side mounting permitted — no gap required between contactors in a multi-contactor group. The 55 mm width and 112 mm height fit standard panel layouts; depth is 164 mm including terminals. Front protection is IP20 (finger-safe), terminal area is IP00 — the wiring compartment is open to the panel environment, so maintain clearance to grounded metalwork per local code. Pollution degree 3 (conductive pollution or dry non-conductive that becomes conductive due to condensation) is rated, typical for industrial control panels not in sealed enclosures.
Thermal and mechanical endurance — switching frequency limits
Maximum switching rates: 1 000 cycles/hour at AC-1 (resistive), 800 at AC-3 (standard squirrel-cage motors), 400 at AC-2, and 300 at AC-4. The AC-4 limit is the binding constraint for reversing or inching duty — exceeding 300 cycles/hour accelerates contact wear. Mechanical life is 10 000 000 cycles typical. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The storage limit governs handling and warehousing, not running conditions.
Termination and wiring — screw terminals, conductor sizes
Main current circuit terminals accept solid conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded conductors: 2x (0.75 to 25 mm²).