It's rated 37 kW at 500 V AC-3 and 18.6 kW at 690 V AC-3, which means it handles the full-load current of a 37 kW induction motor on a 500 V line or a smaller motor on a 690 V supply without derating the contactor. Mounting is screw-and-snap-on onto standard 35 mm or 75 mm DIN rail, so it drops into any panel that already uses the SIRIUS S3 footprint.
The 37 kW at 500 V AC-3 rating is the motor-switching figure that governs real use — AC-3 covers starting and disconnecting squirrel-cage motors under load. The 50 Hz and 60 Hz operating range is 0.8 to 1.1 times the rated voltage, so it holds in on weak grids or genset supplies. That's enough for a conveyor start-stop duty cycle running 8 hours a day, but not for a high-speed pick-and-place application where you'd need a dedicated motor-contactor with a higher mechanical endurance.
The contactor is 70 mm wide, 146 mm high, and 139 mm deep — the S3 footprint. The front has IP20 protection with the cover or box terminal installed, which is the usual for a panel interior; the terminal itself is IP00, meaning it's not touch-safe until the enclosure door is closed. Wire sizes: solid conductors accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), and stranded goes up to 2x (10 to 50 mm²). The main circuit terminals are screw-type, so you'll need a torque screwdriver — no spring-cage here.
For sourcing, this is a quoted-to-order line item. The SIRIUS S3 contactor family is widely stocked by Siemens distributors, but the exact 3RT1044-1AK60 variant with screw terminals and the 500 V / 690 V rating block may not sit on every shelf. An RFQ is the right move to confirm lead time and quantity breaks.