SIRIUS S0 power contactor — what it is and what it fits
The Siemens 3RT2027-2CK64-3MA0 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads and resistive circuits in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 60715, using either screw fixing or the snap-on latch, and its 45 mm width means it occupies a single modular slot in a typical enclosure layout. The coil connection uses spring-type terminals, which speeds wiring and holds up better under vibration than screw clamps — a detail that matters when the panel sees fork-truck rumble or conveyor line chatter.
What the ratings mean for your circuit
The contactor is rated for AC-3 motor switching at up to 750 operations per hour, and AC-1 resistive loads at up to 1 000 cycles per hour. Those are the duty-class limits that govern real-world coil and contact life — the AC-3 figure is the one you size against for a motor start/stop application, not the higher AC-1 number. The arcing time is specified at 10 ms, which is tight enough to keep contact erosion predictable in a standard 50/60 Hz line. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C, so the part handles unheated warehouses and enclosure heat rise without derating.
Mounting and wiring constraints
The contactor accepts solid or stranded conductors from 1 to 10 mm² on the power circuit, and 2x (0.5 to 2.5 mm²) on the auxiliary circuit. The mounting position allows +/-180° rotation on a vertical surface and can be tilted forward or backward by +/-22.5°, which gives flexibility in tight enclosures — you can orient it to keep the spring terminals accessible. Clearance requirements are 10 mm upwards, downwards, and forwards, and 6 mm at the sides, so plan the DIN-rail spacing accordingly. The depth is 144 mm, height 102 mm, so it fits standard 200 mm deep enclosures with room for wiring ducts.