What it is and what the ratings mean
The Siemens 3RT2018-2BM41 is a SIRIUS power contactor in frame size S00, designed for switching motor loads and resistive loads in industrial control panels. Its 220 V DC coil operates within a -25 to +60 °C ambient range, and the spring-type terminals accept solid or stranded conductors from 0.5 to 4 mm² (2x per clamp). The contactor mounts via screw or snap-on onto a 35 mm DIN rail per EN 60715, with +/-180° rotation and +/-22.5° tilt possible on vertical surfaces. The headline switching frequency varies by duty class: at AC-1 (resistive) it handles up to 1,000 operations per hour, at AC-2 and AC-3 (motor starting/running) 750 ops/h, and at AC-4 (plugging/inching) 250 ops/h. The AC-3e rating also caps at 750 ops/h. For DC-13 breaking at 24 V it's rated 10 A, dropping to 0.3 A at 220 V — so the coil voltage determines the inductive load it can interrupt cleanly.
Mounting and integration notes
Width 45 mm, depth 73 mm, height 70 mm. Clearances: 10 mm upward, forward, downward; 6 mm at sides. Main contacts 20...12, auxiliary switch included.