The Siemens SIRIUS 3RT1035-3AL20 is a size S2 power contactor rated for motor switching at 18.5 kW in AC-2 duty at 400 V — that's the slip-ring motor load, not the standard squirrel-cage AC-3 curve. At 500 V it handles 22 kW; at 690 V it's good for 11.4 kW. The screw-type main terminals accept 2x (0.75 to 16 mm²) solid or stranded, and the auxiliary contacts are rated 10 A at 24 V, 2 A at 60 V, 6 A at 230 V. Mechanical life is a typical 10 million operations.
The 55 mm width and 112 mm height fit a standard panel grid; side-by-side mounting is supported with no derating gap. Pollution degree 3 environment (conductive pollution) is within spec.