What this SIRIUS S2 contactor is
The Siemens 3RT5034-1AG00 is a SIRIUS S2 power contactor, screw-type terminals on both main and auxiliary circuits, sized for motor loads up to 31 kW at 400 V 60 °C (54 kW at 690 V 60 °C). Insulation voltage is rated 690 V with a 6 kV surge withstand, so it handles standard 400 V three-phase panels with headroom for 690 V industrial networks. The S2 frame is the mid-size in the SIRIUS contactor family — 55 mm wide, 112 mm tall, 115 mm deep — fitting a standard 35 mm DIN rail per EN 50022, with screw and snap-on mounting.
For fuse coordination, the spec calls for a gL/gG 63 A fuse on the main circuit. That's a standard industrial fuse — no special or hard-to-find part.