SIRIUS S3 power contactor — 175-280 V AC coil, screw terminals
The Siemens 3RT2045-1SP30 is a SIRIUS-brand power contactor in size S3, designed for switching motor loads and resistive circuits in industrial control panels. Its coil is rated for 175-280 V AC (50/60 Hz), drawing 2.4 VA at both frequencies. The main contacts use screw-type terminals accepting solid conductors from 2.5 to 16 mm² and stranded up to 70 mm², with an auxiliary switch built in. Mounting is via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, with a width of 70 mm and depth of 152 mm. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward, giving panel builders flexibility in tight enclosures.
Ratings and what they mean for your application
The 3RT2045-1SP30 is rated for AC-3 switching at up to 1,000 operating cycles per hour (AC-3e also 1,000 1/h), making it suited for frequent starting of squirrel-cage motors. AC-4 duty (plugging/reversing) is limited to 300 1/h, and AC-1 (resistive loads) to 900 1/h. The mechanical life is typically 5,000,000 operations, and the MTBF is listed at 52 years — a reliability figure that supports long service intervals in continuous-process lines. Auxiliary contact ratings: 10 A at 24 V, 2 A at 48 V, and 2 A at 60 V. The inrush current peak is 32 A. Operating temperature range is -25 to +60 °C; storage range -55 to +80 °C. Arcing time is 10-20 ms, and the contactor's opening/closing times (AC and DC) are both 38-57 ms.
Panel integration notes
The S3 contactor occupies 70 mm width on the DIN rail, with 152 mm depth behind the panel. Clearance requirements: 10 mm upward, 10 mm downward, 20 mm forward, and 10 mm at the side. Wire termination uses screw terminals; solid conductors 2.5-16 mm² or stranded 6-70 mm² for the main circuit, and 2x (0.5-1.5 mm²) or 2x (0.75-2.5 mm²) for auxiliary wiring.