SIRIUS S3 Power Contactor, 110 V Coil
The Siemens 3RT1045-1BF40 is a SIRIUS size S3 power contactor with a 110 V AC coil, screw-type terminals for the main circuit, and an IP20 degree of protection on the front when fitted with the cover or box terminal. Rated for AC-3 switching at 500 V delivering 45 kW, and at 690 V delivering 21.1 kW, this contactor handles motor loads typical of pumps, fans, and compressors in industrial control panels. Mechanical life is rated at 10 million operations typical, with maximum switching rates of 1000 cycles per hour in AC-3 duty, 900 in AC-1, 400 in AC-2, and 300 in AC-4.
Mounting and Wiring
Mounts via screw fixing or snap-on onto 35 mm or 75 mm standard mounting rail; side-by-side mounting is supported without derating in standard ambient conditions. Main circuit terminals accept solid conductors from 2x (0.5 to 1.5 mm²) up to 2x (0.75 to 4 mm²) and stranded conductors from 2x (10 to 50 mm²); auxiliary terminals accept 2x (2.5 to 16 mm²) solid or stranded. The terminal block itself carries an IP00 rating, so the overall IP20 protection on the front relies on the cover or box terminal being fitted — plan for panel-side sealing if the contactor is mounted in a washdown or dusty environment.
Environmental and Compliance
Operating temperature range is -25 to +60 °C; storage range extends from -55 to +80 °C. Pollution degree 3 classification means it is suited for industrial atmospheres with conductive pollution. Lifecycle status is current production. RoHS compliance date is 05/01/2012, covering substance prohibitions under EU Directive 2011/65/EU. Arcing time is 10 to 15 ms at rated voltage; DC switching times are 14 to 20 ms. These figures matter when coordinating with upstream protection devices or when the contactor is used in a safety circuit requiring fast dropout.