The Siemens SIRIUS 3RT1326-1AM20 is a size S0 power contactor with four normally-open main contacts, rated for 11 kW at 400 V in AC-2 duty — the standard category for slip-ring motor starting and reversing.
For type 1 coordination the fuse requirement is gL/gG 63 A; for type 2 it drops to 35 A, which affects the upstream protection sizing. The S0 footprint (61 mm wide, 85 mm tall, 91 mm deep) is compact enough for dense rail layouts; side-by-side mounting is allowed with a 6 mm gap between units. The solid and stranded wire ranges (0.5–4 mm² for control, 1–10 mm² for power) cover typical panel wiring without needing adapters.