The 30 kW at 500 V in AC-3 duty handles standard squirrel-cage motors — starting and stopping on the fly. That's the rating that matters for most conveyor, pump, and fan circuits.
AC-2 at 400 V: 22 kW. That's the contactor's rating for slip-ring motors or other loads where the contacts close and open under current. AC-3 at 500 V: 30 kW. This is the standard rating for direct-on-line starting of cage motors. At 690 V it's rated 11.4 kW, which covers most 690 V motor circuits in European industrial plants. Screw terminals accept solid 2x (0.25 to 2.5 mm²) and stranded 2x (0.75 to 25 mm²) — covers most control and power wiring up to 25 mm², which is good for the current levels this contactor handles.