The Siemens 3RT1017-1AN04 is a SIRIUS power contactor in the S00 frame size — the smallest footprint in the SIRIUS family, meant for motor loads up to about 5.5 kW at 400 V.
AC-4 at 400 V is 8.5 A — that's the plugging / inching duty rating, the one that matters for frequent reversing or jogging. AC-2 at 400 V carries 5.5 kW, which covers slip-ring motor starting. For standard AC-3 squirrel-cage duty at 400 V, it's also 5.5 kW. The coil holds between 0.8 and 1.1 times rated voltage at 50 Hz (0.85 to 1.1 at 60 Hz), so it stays pulled in through brownouts down to about 176 V on a 220 V coil.
Screw terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid/stranded, plus 1x 12 AWG. The auxiliary contact block has 2 normally-open instantaneous contacts, rated 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. For type 2 coordination, the required upstream fuse is gL/gG 20 A; type 1 coordination allows 35 A.