Siemens 3RT1044-1AG20 — SIRIUS S3 Power Contactor
This is a screw-type terminal unit, which means you're wiring with a screwdriver, not pushing in ferrules. The main circuit accepts stranded up to 2x (10…50 mm²), so it'll take a 35 mm² motor feed without adapters. Solid and stranded control wiring lands on the 2x (0.5…1.5 mm²) and 2x (0.75…2.5 mm²) terminals.
The 37 kW at 500 V AC-3 rating is the number that governs motor switching — that's a 50/60 Hz three-phase induction motor up to that shaft power. The 18.6 kW at 690 V covers higher-voltage industrial networks common in mining or marine installations. AC-3 means it's rated for starting and disconnecting squirrel-cage motors under load. That's well into the millions for a contactor that'll see maybe a few hundred thousand cycles in a conveyor or pump application — it's not the wear-out item in the panel. The IP20 rating on the front with cover or box terminal means the front is finger-safe, but the terminal area is IP00 — keep tools and fingers clear of the connection points when live.