The Siemens SIRIUS 3RT1044-1AR00 is a Size S3 power contactor built for motor switching in industrial control panels. It lands in the AC-4 duty class at 55 A on 400 V — that's the rating that governs reversing or plugging applications where the contactor makes and breaks stalled-rotor current. For less severe AC-2 duty (slip-ring motors), it's rated at 30 kW at 400 V, and at 500 V it handles 37 kW in standard AC-3 motor starts. Mounting is screw-and-snap-on onto 35 mm or 75 mm standard DIN rail. The main circuit uses screw-type terminals, and side-by-side mounting is allowed — no derating gap required between units on the rail. Pollution degree 3 means it's rated for industrial environments with conductive contamination. Operating temperature spans -25 to +60 °C, storage from -55 to +80 °C. The front face carries IP20 protection (with cover or box terminal); the terminal area itself is IP00 — so panel builders need to account for clearance in the enclosure design.
Terminal & Wiring Detail
Power circuit accepts solid conductors: 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), max 2x (0.75...4 mm²). Stranded connections go up to 2x (10...50 mm²). The control circuit (coil) uses a separate terminal set: 2x (2.5...16 mm²) solid or stranded. These are screw-clamp terminals — strip lengths and torque specs follow standard Siemens SIRIUS practice.
Dimensional Fit
Footprint is 146 mm high by 70 mm wide by 139 mm deep. The 70 mm width allows side-by-side mounting.
Switching Performance & Coil Data
Arcing time is 10 to 15 ms; total make/break time at AC is 10 to 19 ms. Coil operates at 50 Hz with voltage tolerance 0.8 to 1.1. Mechanical life is 10 million operations.
Auxiliary Contact Ratings
Integrated auxiliary contacts (the 1AR00 variant includes one normally-open and one normally-closed) are rated: 10 A at 24 V, 6 A at 230 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 3 A at 400 V. At 690 V the auxiliary is rated 18.6 kW; at 1000 V it's 30 W — these are the switching limits for the control circuit, not the main poles.