Siemens SIRIUS 3RT1045-1XB40-0LA2 — Power Contactor, Size S3, 24 VDC Coil
The Siemens SIRIUS 3RT1045-1XB40-0LA2 is a size S3 power contactor rated for motor switching at 45 kW at 500 V and 21.1 kW at 690 V, with a 24 VDC coil drawing 10 A at rated voltage. It mounts via screw or snap-on onto 35 mm or 75 mm standard DIN rails, fitting into a 70 mm wide, 176 mm tall, 152 mm deep footprint — a compact frame for its power class. The main circuit uses screw-type terminals accepting up to 50 mm² stranded wire, with auxiliary wiring accommodating solid conductors from 0.5 to 4 mm². Operating temperature spans -40 to +70 °C, with storage down to -55 °C, making it suitable for unconditioned enclosures in industrial environments.
Switching Performance and Mechanical Life
Rated for 1,000 operations per hour in AC-3 duty (motor switching) and 900 ops/h in AC-1 (resistive loads), with a typical mechanical life of 10,000,000 cycles. The arcing time is 10 to 15 ms, and the DC switching capacity at 24 V is 10 A, dropping to 0.3 A at 220 V DC — important for DC auxiliary circuits or brake control.
Mounting and Clearance
Side-by-side mounting is permitted without derating. Minimum clearances to adjacent components: 10 mm upwards, 10 mm downwards, 10 mm at the side, and 20 mm forwards. This allows dense panel layouts while maintaining arc-flash and thermal separation.