What it is and where it lands
The Siemens 3RT2018-1AD02 is a SIRIUS power contactor in the Size S00 frame, built for switching motor and resistive loads in control panels. It carries a 24 VDC coil with screw-type terminals and includes an auxiliary switch. The contactor mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, so it integrates into standard panel layouts without adapters.
Key ratings and what they mean for fit
The 24 VDC coil draws 10 A at rated value — that's the holding current, not the pickup surge. The contactor is rated for AC-3 duty at 750 operating cycles per hour maximum, which covers standard motor switching for pumps, fans, and conveyors. For heavier AC-4 duty (plugging, inching), the maximum drops to 250 cycles per hour — respect that derating if the application involves frequent reversing or jogging. Mechanical life is typical 30 million operations. The auxiliary switch is built in.
Mounting and clearances
The Size S00 footprint is 45 mm wide, 58 mm high, 73 mm deep. For side-by-side DIN rail mounting, allow 6 mm clearance at the side, 10 mm upwards, 10 mm downwards, and 10 mm forwards for arc chute venting and wiring access. The mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/-22.5° — useful when the panel layout forces a non-standard orientation.
Wire termination
Main contact terminals accept solid or stranded wire from 0.5 to 4 mm². For two-wire termination, it accepts 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or 2x 4 mm². Coil terminals are screw-type.
Environmental and compliance
Operating temperature range is -25 to +60 °C during operation, with storage from -55 to +80 °C. The arcing time at AC is 4 to 15 ms, with a typical arcing time of 10 to 15 ms — relevant for coordination with upstream overcurrent devices. The contactor operates at both 50 Hz and 60 Hz with the same 0.25 A coil draw at each frequency.