What it is and what it does
The Siemens 3RT2018-1AM21-0UA0 is a SIRIUS-brand power contactor in the compact Size S00 frame. It is designed for switching motor loads and resistive loads in industrial control panels, with a rated operational current that depends on the duty cycle and voltage — the AC-3 maximum switching rate is 750 operations per hour, and the AC-4 maximum is 250 operations per hour. The contactor includes an auxiliary switch and uses screw-type terminals for the magnet coil.
Panel integration and mounting
This contactor mounts via screw fixing or snap-on onto a 35 mm DIN rail per DIN EN 60715. The Size S00 footprint is 45 mm wide, 58 mm high, and 73 mm deep, so it occupies a single DIN-rail module width. It can be mounted in any orientation within ±180° rotation on a vertical surface, and can be tilted forward or backward by ±22.5°. Minimum clearances for ventilation: 10 mm upwards, 10 mm downwards, 10 mm forwards, and 6 mm at the sides.
Wiring and termination
The main contact terminals accept solid or stranded conductors from 0.5 to 4 mm², or two conductors per terminal: 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or 2× 4 mm². The coil connection uses screw-type terminals. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.