SIRIUS S0 power contactor for motor loads
The Siemens SIRIUS 3RT2027-1AU60 is a size S0 power contactor rated to switch motor loads at 27 A in AC-3 duty at 480 V — that covers a 15 hp motor at 460-480 V three-phase, common on North American 480 V distribution. It mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, and the mounting position allows ±180° rotation on a vertical surface plus ±22.5° tilt forward/backward — useful when you need to orient the contactor to fit existing panel wiring or cable entry. The main contact wire range accepts solid or stranded conductors from 1 to 10 mm² (roughly 18 to 8 AWG), and the screw terminals on the magnet coil are the same type — no special tooling beyond a standard screwdriver.
Duty cycle and thermal limits
Switching frequency depends on the duty class: 1 000 operations per hour for AC-1 resistive loads, 750/h for AC-2 and AC-3 motor starting, and 250/h for AC-4 inching/plugging. Operating temperature range is -25 to +60 °C; storage range extends to -55 to +80 °C. Mechanical life is rated at 10 million operations typical — that's the contactor itself, not the contacts under load.
Auxiliary contact switching capacity
The built-in auxiliary switch handles 10 A at 24 V, 2 A at 48/60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, 3 A at 400 V, and 0.6 A at 440 V — a broad curve that covers most control voltage levels in mixed-voltage panels.