What It Is and Where It Fits
The Siemens SIRIUS 3RT2026-2BW40 is a size S0 power contactor with a 48 VDC coil, designed for switching motor loads in industrial control panels. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, so it drops into any standard panel layout without special brackets. Spring-type terminals on the magnet coil accept solid or stranded wire from 1 to 10 mm², and dual-wire entry (2x 0.5 to 2.5 mm²) is supported for daisy-chaining control wiring. This saves a terminal block row in dense panels.
Key Ratings and What They Mean for Your Load
At 230 V, the contactor is rated for 3 hp motor loads — that covers typical small pumps, fans, and conveyors in light industrial lines. At 400 V, it switches 3 A, suitable for smaller three-phase motors or resistive heater banks. DC switching capability at 48 V is 2 A, which matters if you're breaking DC control circuits or small DC motor loads — the arc extinguishes differently than AC, so this rating is the one to check for DC applications. Maximum mechanical life is 10 million operations, with electrical life depending on load category: 1000 cycles/hour at AC-1 (resistive), 750 at AC-3 (motor running), and 250 at AC-4 (plugging/inching). For high-cycle applications like conveyor indexing, stay within the AC-3 or AC-4 limits to avoid premature contact wear. Arcing time is 10 ms, and DC operating time (pull-in/drop-out) is 15 to 17.5 ms — fast enough for most sequencing but worth noting if your safety circuit requires a specific break time.
Panel Integration and Clearance
Dimensions are 45 mm wide, 102 mm high, and 107 mm deep — the S0 frame fits in a standard 45 mm slot on the DIN rail, leaving room for adjacent contactors or overload relays. Required clearances: 10 mm upward, 10 mm downward, 10 mm forward, and 6 mm at the sides. These ensure proper ventilation and wiring access; skimping on side clearance when mounting multiple contactors side-by-side can trap heat. Mounting position is flexible: the contactor can be rotated ±180° on a vertical surface and tilted ±22.5° forward or backward. This helps when fitting into angled sub-panels or tight enclosures where a flat vertical mount isn't possible.
Environmental and Lifecycle
Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. This covers most indoor industrial environments; for outdoor cabinets in direct sun, verify the internal enclosure temperature stays under 60 °C.