What it is and what it does
The Siemens 3RT2026-1AU60 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads and resistive loads in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 60715, using either screw fixing or the integrated snap-on latch, and accepts solid or stranded conductors from 1 to 10 mm² on the main circuit. The headline rating is 21 A at 480 V in AC-3 duty (switching squirrel-cage motors), which is the rating that governs motor load selection. For resistive loads (AC-1), the contactor can switch up to 1 000 operations per hour, while AC-3 motor switching is rated at 750 operations per hour. At 230 V, it carries a 3 hp motor load.
What the ratings mean for fit
The 21 A AC-3 rating at 480 V means this contactor can switch a 3-phase induction motor drawing up to 21 A under starting and running conditions — the standard IEC utilization category for motor starting. The AC-1 rating (resistive) is not explicitly stated as a current value, but the 1 000 cycles/hour switching frequency indicates it handles continuous resistive loads at a higher duty cycle than motor loads. The contactor includes an auxiliary switch (screw-type terminals for the coil), and its mechanical life is rated at 10 000 000 operations typical. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. The mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/-22.5°. Clearance requirements are specified: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. The 45 mm width (3 module spaces on a DIN rail) and 85 mm height fit standard panel layouts. Depth is 97 mm, which matters for enclosure depth selection.