SIRIUS S2 Power Contactor — 11 kW AC-2 Motor Duty
The Siemens SIRIUS 3RT1336-3XF48-0LA3 is a size S2 power contactor rated for 11 kW at 400 V in AC-2 duty (slip-ring motor starting), and 23 kW at 230 V for AC-1 resistive loads. That AC-2 rating is the one that governs motor switching — it tells you the contactor handles the higher inrush and arcing of wound-rotor motors, not just resistive heaters. Insulation voltage is rated 690 V, with a pollution degree of 3, so it's suited for industrial panels where conductive dust or condensation is present. The front face carries IP20 finger protection; the terminal area is IP00 — meaning the wiring zone is exposed and requires enclosure-level protection. Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022. Side-by-side mounting is permitted, which saves rail space when grouping multiple contactors in a motor control center.
Switching Capacity Across Voltages
For DC loads, the contactor is rated 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. These are the make/break capacities — the DC arc is harder to extinguish than AC, so the current drops sharply as voltage rises. For AC loads at 230 V it handles 6 A, and at 400 V it handles 3 A. Arcing time is 10 to 15 ms on AC, and 15 to 30 ms on DC. The built-in varistor surge suppressor (design) clips voltage spikes from the coil, which extends contact life and reduces EMI on the control wiring.
Termination and Wiring
Main current circuit uses screw-type terminals accepting 2x (0.75 to 25 mm²) stranded or 2x (0.25 to 2.5 mm²) solid, with a minimum 16 mm² at both 40 °C and 60 °C ambient. AWG range is 2x (18 to 2). The auxiliary and control circuit uses spring-loaded terminals — no screw tightening needed, which speeds panel wiring and avoids loose connections from vibration.
Environmental and Endurance
Operating temperature range is -40 to +70 °C; storage range is -55 to +80 °C. Mechanical endurance is 10 million operations typical. Maximum switching rate at AC-1 is 1,000 cycles per hour. These numbers matter for high-cycling applications like conveyor or pump start-stop duty.