SIRIUS Size S0 power contactor — 24 VDC coil, spring terminals
The Siemens SIRIUS 3RT2027-2FB44-3MA0 is a Size S0 power contactor with a 24 VDC coil and spring-type terminals, designed for screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715. Rated for AC-3 motor duty at 5 hp on 230 V, this contactor handles switching frequencies up to 750 operations per hour in AC-3 and AC-3e duty, and 250 per hour in AC-4 (plugging/reversing) duty. The 24 VDC coil holds at 0.8 of rated voltage (19.2 V) and drops out in 15 to 18 ms; arcing time is 10 ms.
Mounting and integration — DIN rail, clearance, wire sizes
Mounts on 35 mm DIN rail (DIN EN 60715) via screw and snap-on; the mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward or backward. Clearance distances: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side. Spring-type terminals accept solid or stranded wire from 1 to 10 mm², or 2x 0.5 to 2.5 mm² stranded. Dimensions are 45 mm wide, 102 mm high, 154 mm deep — the S0 frame fits standard panel layouts.
Duty ratings and switching frequency
Maximum switching frequency depends on duty: 1,000 ops/h at AC-1 (resistive), 750 ops/h at AC-2 and AC-3, 750 ops/h at AC-3e, and 250 ops/h at AC-4. Auxiliary contact breaking capacity at 24 VDC is 6 A, derating to 0.3 A at 220 VDC. Mechanical life is rated at 10 million operations typical.
Environmental range and lifecycle
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.