The Siemens SIRIUS 3RT6027-1BW40 is a Size S0 power contactor rated for motor switching at 27.5 kW at 400 V (60 °C ambient) in AC-3 duty, with a maximum AC-3 rated voltage of 690 V. It uses screw-type terminals for both main and auxiliary circuits, and mounts via screw or snap-on onto 35 mm DIN rail per EN 50022.
Motor ratings and thermal headroom
Rated motor power at 60 °C ambient is 15.5 kW at 230 V, 27.5 kW at 400 V, and 47.5 kW at 690 V. The 60 °C rating means this contactor holds its full load current without derating in a warm panel — useful for enclosures with multiple devices or limited ventilation. The 690 V AC-3 ceiling covers 480 V and 575 V systems with margin.
Panel integration and wiring
Width is 45 mm (single S0 footprint), depth 107 mm, height 85 mm. The 45 mm width fits standard 45 mm pitch on DIN rail, leaving room for adjacent devices without oversizing the enclosure. Main circuit terminals accept 2x (0.5–1.5 mm²) or 2x (0.75–2.5 mm²) solid/stranded, or AWG 2x (16–12) / 2x (14–8). Side-by-side mounting is permitted — no spacing required between units.