What This Part Is and Where It Fits
The Siemens 3RT1046-1CP04-0KV0 is a SIRIUS power contactor in the S3 frame size, designed for switching motor loads in industrial control panels. It's rated for 55 kW at 500 V in AC-3 duty, which covers the majority of three-phase induction motor starts across pumps, fans, and conveyors. The 45 kW at 400 V AC-2 rating handles slip-ring or wound-rotor motors where the load is switched under reduced current. For reversing or inching applications, the AC-4 rating at 80 A at 400 V tells you the contactor can handle the higher electrical wear of plugging or jogging without premature contact welding.
Mounting and Integration
Mounts via screw or snap-on onto 35 mm or 75 mm standard DIN rail. The 70 mm width and 146 mm height fit a standard S3 footprint, and side-by-side mounting is allowed — no derating gap required for adjacent contactors in a motor control center. Depth is 188 mm, so check your enclosure depth before panel layout. The main circuit uses screw-type terminals; solid wire from 0.5 mm² up to 4 mm² per clamp, stranded up to 50 mm² for the power feed. The front face carries IP20 protection with the cover or box terminal installed; the terminal body itself is IP00, meaning the live parts are exposed behind the panel door.
Auxiliary Contact Ratings
Built-in auxiliary contacts are rated at 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. For DC switching, the ratings drop to 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — the DC arc extinction is harder, so stay within these limits for PLC or relay coil loads. Power dissipation at 1000 V is 37 W, which matters for thermal budgeting inside a sealed enclosure.