What It Is and Where It Fits
The Siemens SIRIUS 3RT2026-1BW44 is a 3-pole power contactor in the S0 frame size, designed for switching motor loads and resistive loads in industrial control panels. Its 48 V DC coil with screw-type terminals makes it a direct fit for panels where a 48 VDC control bus is already in place — common in older European machine builds or sites running a dedicated 48 VDC safety/control supply. The contactor mounts on a 35 mm DIN rail per DIN EN 60715, either snapped on or screwed down, and accepts solid or stranded conductors from 1 to 10 mm² on the main contacts.
Key Ratings and What They Mean for Fit
The headline rating is 1.1 A at 400 V AC-3 (full-scale value), which is the current it can switch for standard squirrel-cage motors during starting and running — that's a small motor, roughly 0.37 kW at 400 V three-phase. For DC breaking, the contactor is rated 6 A at 24 V, 2 A at 48 V, and 0.3 A at 220 V; these figures govern its use in DC load circuits, not the coil supply. The mechanical life is 10 million operations typical, and the maximum switching frequency varies by duty: 1000 cycles/hour for AC-1 (resistive), 750 for AC-2 and AC-3 (motor starting/running), and 250 for AC-4 (plugging/inching). If your application involves frequent reversing or inching, the AC-4 limit of 250 cycles/hour is the binding constraint — don't exceed it.
Mounting and Clearance
The contactor measures 45 mm wide, 85 mm tall, and 151 mm deep. It can be mounted on a vertical surface with +/-180° rotation and tilted forward/backward by +/-22.5°, which gives flexibility in tight enclosures. Required clearances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the sides. The operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. No auxiliary switch is included on this variant — if you need one, it must be added separately.