What it is and what it does
The Siemens 3RT1046-1BP40 is a SIRIUS power contactor in the S3 frame size, designed for switching motor loads and resistive loads in industrial control panels. It mounts on standard 35 mm or 75 mm DIN rail via screw or snap-on fastening, and is rated for side-by-side mounting without derating when the ambient stays within -25 to +60 °C. The key motor ratings: 55 kW at 500 V (AC-3 duty) and 45 kW at 400 V (AC-2 duty). For heavy jogging or inching duty (AC-4), it carries 80 A at 400 V. These numbers define the load it can switch — a 55 kW pump on 500 V, or a 45 kW conveyor on 400 V, with the AC-4 rating covering the high-stress starts and reversals that wear standard contactors faster.
Mounting and wiring
The main current circuit uses screw-type terminals. Solid wire capacity: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded: 2x (10 to 50 mm²). The front face is IP20 (finger-safe with cover/box terminal); the terminal area itself is IP00 — so the panel builder needs to account for clearance around the lugs. Pollution degree 3 means it's rated for industrial environments with conductive dust or condensation. Dimensions: 146 mm high, 70 mm wide, 152 mm deep. The 152 mm depth is the main dimension to check against gland-plate clearance or enclosure depth — it's deeper than a typical S2 contactor, so verify the back-of-panel clearance before committing the layout.