SIRIUS 3RT1045-1BV40 Power Contactor — Size S3, 45 kW at 500 V
The Siemens 3RT1045-1BV40 is a SIRIUS power contactor in size S3, designed for switching motor loads and resistive circuits in industrial control panels. Its AC-3 rating of 45 kW at 500 V means it handles standard squirrel-cage motor starting and stopping up to that power level — the rating that governs real motor duty, not the higher AC-1 resistive figure. Mounts via screw and snap-on onto 35 mm or 75 mm standard mounting rail, with side-by-side mounting permitted for dense panel layouts. Pollution degree 3 (conductive pollution typical in industrial environments) is accommodated, so no additional derating for dirty air in the enclosure. Main circuit connections are screw-type terminals, accepting solid conductors up to 2x 4 mm² or stranded up to 2x 50 mm² — sized for the full rated current without needing lug adapters. The front face carries IP20 protection (finger-safe with cover/box terminal); the terminal area itself is IP00, so live parts are exposed inside the panel — standard for this class.
Switching Performance and Mechanical Life
Rated for 1,000 operations per hour at AC-3 duty, 900 at AC-1, 400 at AC-2, and 300 at AC-4 — the AC-4 figure is the limiting case for plugging or inching applications. Mechanical life is typical 10,000,000 operations, so the contactor outlasts most panel designs in normal cycling. Arcing time is 10 to 15 ms; at DC the arcing time extends to 14 to 20 ms. The DC switching ratings are 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — resistive loads only; inductive DC loads require derating or arc-suppression external to the contactor.