Wye-delta contactor assembly for motor starting
The Siemens SIRIUS 3RA1445-8XB20-1AL2 is a pre-assembled wye-delta contactor assembly designed to reduce inrush current during three-phase motor starting. It integrates three contactors in a single unit with screw fixing and IP20 front protection, sized for a 75 kW motor at 400 V. Rated 150 A in AC-3 duty at 400 V, this assembly switches motor loads up to that current — the AC-3 rating governs the inductive motor load, not the resistive AC-1 curve.
Mounts via screw fixing on a vertical surface, rotatable ±180° and tiltable ±30° front/back. Side-by-side spacing of 0 mm is permissible for grounded parts, keeping panel width tight. Dimensions are 218 mm wide, 180 mm high, 194 mm deep — plan for this footprint when laying out the enclosure.