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.
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.
Width is 45 mm (single S0 footprint), depth 107 mm, height 85 mm. 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.