Siemens SIRIUS 3RT1045-1AF00-1AA0 — power contactor, size S3
The Siemens SIRIUS 3RT1045-1AF00-1AA0 is a size S3 power contactor rated for 45 kW at 500 V in AC-3 duty — the motor-switching category that governs most induction-motor starts and stops. Mounting is via screw or snap-on onto 35 mm and 75 mm standard mounting rail — the 70 mm width means it occupies three 18 mm module positions on a 35 mm DIN rail, or two on a 75 mm rail. The IP20 front protects against finger contact in the panel; the terminal area itself is IP00, so live parts are exposed once the cover is off — standard for power-contactored panels where the gland plate and door interlock provide the outer barrier. Side-by-side mounting is permitted, which keeps the rail fill factor tight when grouping multiple contactors.
Main circuit terminals are screw-type. Solid conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded: 2x (10 to 50 mm²). Auxiliary contact capacity: at 24 V rated value 10 A, at 60 V rated value 2 A, at 110 V rated value 1 A, at 220 V rated value 0.3 A, at 230 V rated value 6 A, at 400 V rated value 3 A (–). The 230 V 6 A rating covers most control-circuit loads in European panels; the 24 V 10 A handles PLC outputs or relay coils without an intermediate interface.
Operating cycle ratings and thermal limits
Maximum switching frequency: AC-1 (resistive) 900 ops/h, AC-2 (slip-ring motor) 400 ops/h, AC-3 (squirrel-cage motor) 1000 ops/h, AC-4 (plugging/inching) 300 ops/h (–). The AC-3 1000 ops/h ceiling is high enough for most conveyor and pump cycling; if your application needs frequent inching or reversing, the AC-4 300 ops/h limit is the binding constraint. Mechanical life typical 10,000,000 operations. Arcing time at AC: 10 to 25 ms, with a narrower 10 to 15 ms window for the main arc. Operating factor at 50 Hz: 0.8 to 1.1.
RoHS compliance date: 05/01/2012.