What it is and where it fits
The Siemens SIRIUS 3RT2027-1DB44-3MA0 is a Size S0 power contactor with a 24 VDC coil and screw-type terminals, designed for screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715. The S0 frame is a common panel footprint — 45 mm wide, 85 mm tall, 151 mm deep — so it fits standard 45 mm DIN-rail pitch without crowding adjacent devices. Mounting position is flexible: the contactor can be rotated ±180° on a vertical surface and tilted forward or backward by ±22.5°, which simplifies layout in tight enclosures.
Switching duty and what the ratings mean
The 24 VDC coil draws 6 A at rated value, with a pick-up threshold of 0.8 x rated voltage and an arcing time of 10 ms — the dropout and arc characteristics matter for DC load circuits where inductive kickback needs to be managed. Switching frequency varies by duty class: 1 000 cycles/hour at AC-1 (resistive loads), 750 cycles/hour at AC-2 and AC-3 (motor starting/running), and 250 cycles/hour at AC-4 (plugging/inching). The AC-3e rating also caps at 750 cycles/hour. For a conveyor or pump motor on AC-3 duty, plan for 750 operations per hour maximum. DC switching capacity is derated by voltage: 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. The 400 V DC rating is unusual for a contactor this size — verify the load type against the DC-1/DC-3 curve if using at that voltage.
Environmental and mechanical limits
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The storage limit is for handling and warehousing, not running — the operating range governs panel ambient. Clearance distances: 10 mm upwards, forwards, and downwards; 6 mm at the sides. These are the minimum air gaps to adjacent metalwork or other devices — factor them into the DIN-rail layout. Wire sizes: solid or stranded 1 to 10 mm² for main contacts; auxiliary circuits accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²). The screw terminals are rated for these ranges — no special ferrules required for the main power wires.