What it is and what it does
The Siemens 3RT1317-2BA40 is a SIRIUS power contactor in the compact S00 frame size, designed for switching motor loads in control panels. Its 4 normally-open main contacts handle resistive and light inductive loads up to 10 A AC-12, and motor starting duty up to 5.5 kW at 400 V AC-2. The 24 VDC magnet coil draws 3.3 W both on pick-up and hold, so the coil suppression circuit sees the same steady-state load.
Mounting and integration
Snaps onto 35 mm DIN rail per EN 50022, or screws directly to a backplate. At 45 mm wide and 72 mm deep, the S00 footprint leaves room for auxiliary contact blocks on the front and side — the 6 mm side clearance is the minimum to adjacent devices for heat dissipation. Spring-loaded terminals on the main circuit accept 2x 0.25–2.5 mm² solid or stranded, or 2x 24–14 AWG. No ring lugs needed; strip and push.