The Siemens 3RT2027-2AR60 is a SIRIUS power contactor in the Size S0 frame — the compact workhorse for switching motor loads in control panels up to around 7.5 kW at 400 V AC-3. The 45 mm width keeps DIN-rail density high in a multi-contactor starter section.
For heavier AC-4 duty (plugging, inching, reversing under load) the limit drops to 250 cycles/h, so if your application requires frequent reversing or jogging, factor that into the thermal budget. The AC-1 resistive load rating goes up to 1,000 cycles/h for heater or lighting banks. Auxiliary contact ratings are given per voltage: 10 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 coil itself terminates on spring-type terminals, which speed up panel wiring compared to screw clamps.
Mounting and Clearance Notes
These are the air and arc-blast gaps — respect them for proper arc extinction and to avoid flashover between adjacent contactors in a row. Wire range: solid or stranded 1 to 10 mm² for the main power circuit, and 2x (0.5 to 2.5 mm²) for the auxiliary/coil connections. The spring terminals on the coil accept ferruled stranded as well — strip length per the terminal marking.