Siemens SIRIUS 3RT7027-1AB05 — Size S0 Contactor, 24 VAC Coil
The front and terminal areas carry IP20 protection, suitable for enclosed panel installations where finger-safe access is required. Coil power draw is 0.82 W on closing and 0.24 W holding at DC, making it compatible with standard 24 V control transformers and PLC outputs without excessive inrush burden.
The Size S0 footprint (55 mm wide, 85.5 mm high, 91 mm deep) fits standard panel layouts; side-by-side mounting is permitted without derating gaps. Ambient operating range is -10 to +55 °C; storage range -25 to +70 °C. Screw terminals accept 2x (0.5…1.5 mm²) solid or stranded, or 2x (0.75…2.5 mm²) finely stranded with ferrule.
Switching Performance and Contact Ratings
Rated operational current at AC-3 (motor switching) is 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V. Maximum switching frequency is 800 cycles/hour at AC-3 and 250 cycles/hour at AC-4 (plugging/reversing). For DC-13 (solenoid/brake) loads at 220 V, the contactor is rated 0.3 A. Surge voltage resistance is 6 kV, and shock resistance is 12.5g / 5 ms (sine pulse at AC). Auxiliary contacts are rated for PLC-level reliability (17 V, 5 mA), ensuring clean signal switching to digital inputs without contact wetting issues.
Protection and Coordination
For type of coordination 2 (short-circuit protection with minimal damage to contactor), use gL/gG NH fuse 3NA: 50 A. For type 1 coordination (no damage to enclosure/personnel, contactor may need replacement), use 125 A. The contactor supports product extension auxiliary switch blocks (screw-type for auxiliary/control circuit), allowing field addition of NO/NC aux contacts without removing wiring.