What it is and what it does
The Siemens SIRIUS 3RT1045-1AN60 is a power contactor in the S3 frame size, designed for switching motor loads in industrial control panels. It's rated for 45 kW at 500 V and 21.1 kW at 690 V under AC-3 duty, meaning it handles the inductive load of a standard three-phase motor up to those power levels without derating. The contactor mounts on a 35 mm or 75 mm DIN rail via screw and snap-on fastening, so it fits into a standard panel layout without extra brackets. Side-by-side mounting is supported, which keeps the rail footprint tight when you're stacking multiple contactors.
Key ratings and what they mean for your panel
The AC-3 maximum switching frequency is 1,000 operations per hour, which is typical for a contactor this size — plenty for a conveyor or pump cycling several times a minute, but not for a high-speed pick-and-place application where you'd need a dedicated contactor with a higher mechanical life or a solid-state relay. The operating temperature range is -25 to +60 °C, so it's fine for most indoor industrial environments, including unheated warehouses in colder climates. The storage range extends to -55 to +80 °C, which covers shipping and off-season storage. The front of the contactor carries an IP20 rating, meaning it's touch-safe for finger access per IEC 60529. The terminal area is IP00, so you'll need to keep the panel door closed or add a terminal cover if the panel is live during maintenance.
Wiring and termination
The main current circuit uses screw-type terminals. Solid conductors can be terminated as 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or up to 2x (0.75 to 4 mm²) maximum. Stranded conductors accept 2x (10 to 50 mm²), which covers the feeder cable for a motor up to about 45 kW at 500 V. The contactor depth is 139 mm, width 70 mm, and height 146 mm — that's a compact footprint for the S3 frame. If you're replacing an older contactor in a tight panel, measure the existing DIN-rail space; the width is the critical dimension for side-by-side fit.