The Siemens 3RT2027-2DB44-3MA0 is a SIRIUS power contactor in the Size S0 frame, designed for switching motor loads and resistive loads in industrial control panels. It mounts on 35 mm DIN rail per DIN EN 60715 via screw or snap-on fastening, and the coil is rated at 24 VDC with a pickup of 0.8 x rated value. The main contact rating is 18-8 A, and the contactor uses spring-type terminals for the magnet coil connection.
Sizing and switching duty
This Size S0 contactor is rated for main contacts at 18-8 A, meaning it handles motor starting currents up to that range in AC-3 duty. The switching frequency varies by load: up to 1 000 operations per hour at AC-1 (resistive), 750/h at AC-2 and AC-3 (motor), and 250/h at AC-4 (plugging/inching). The AC-3e rating also allows 750/h. For DC switching, the contactor is rated at 6 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V — these are the values that govern DC load switching, not the AC rating.
Mounting and clearances
The contactor measures 154 mm deep, 102 mm high, and 45 mm wide. It mounts on 35 mm DIN rail per DIN EN 60715, with screw or snap-on fastening. The mounting position allows +/-180° rotation on a vertical surface and can be tilted forward/backward by +/-22.5°. Required clearances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. The operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.
Termination and wiring
The magnet coil uses spring-type terminals. Main circuit connections accept solid or stranded conductors from 1 to 10 mm². Auxiliary contacts (if present) accept 2x (0.5 to 2.5 mm²) solid or stranded. The arcing time is 10-10 ms, and the DC operating time is 15-18 ms. No auxiliary switch is included on this variant.