SIRIUS 3RT2027-2KB40 — Coupling Contactor, S0 Frame
The Siemens 3RT2027-2KB40 is a SIRIUS coupling contactor in the S0 frame size, designed for switching loads in control panels and motor control centers. It uses a 24 VDC coil rated at 10 A and terminates through spring-type terminals, accepting solid or stranded conductors from 1 to 10 mm². Mounting is by screw or snap-on onto 35 mm DIN rail per DIN EN 60715, with ±180° rotation and ±22.5° tilt allowed on vertical surfaces.
Key Ratings and What They Mean for Fit
The 10 A rating at 24 VDC is the maximum continuous current the main contacts can carry in DC-1 duty — useful for resistive or lightly inductive DC loads. For motor switching, the AC-3 rating governs; the contactor is sized for S0-frame motor loads typical in small conveyors, pumps, and fans. The switching frequency limits are 1,000 cycles/hour in AC-1, 750 in AC-2/AC-3, and 250 in AC-4 (–) — AC-4 is the hardest duty (plugging/inching), so if your application requires frequent reversing, stay at or below 250 ops/hr to avoid premature contact wear. Spring-type terminals accept 1–10 mm² solid or stranded and also 2x 0.5–2.5 mm². The 45 mm width and 107 mm depth fit standard S0 panel cutouts. Minimum clearances: 10 mm upward/downward/forward, 6 mm at the side. Operating temperature is -25 to +60 °C; storage range is -55 to +80 °C.