What it is and what it does
The Siemens SIRIUS 3RT2027-2AV00 is a size S0 power contactor designed for switching motor loads and resistive loads in industrial control panels. It is rated 27 A at 480 V in AC-3 duty (motor switching) and 5 hp at 230 V, so it handles typical three-phase motors up to that horsepower without derating. The contactor includes an auxiliary switch block, saving a separate add-on for basic status feedback.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The S0 footprint — 45 mm wide, 102 mm tall, 97 mm deep — fits standard panel layouts; the 45 mm width matches a single 9 mm module pitch multiplied by five, so it occupies five adjacent slots on the rail. Clearance requirements: 10 mm upwards, 10 mm downwards, 10 mm forwards, 6 mm at the side. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, useful when the panel layout forces an unconventional orientation.
Ratings and what they mean for your application
AC-3 rated 27 A at 480 V means this contactor can switch a three-phase motor drawing 27 A under full-load starting conditions — the typical duty for conveyors, pumps, and compressors. The AC-1 rating (resistive load) is not explicitly listed, but the AC-3 figure is the one that governs motor selection. For high-inertia loads or plugging duty (AC-4), the maximum switching rate drops to 250 operations per hour, so it is not intended for frequent reversing or jogging applications. The coil terminals are spring-type, accepting 1 to 10 mm² solid or stranded wire, which speeds wiring compared to screw terminals.