The Siemens 3RT2025-1AL20 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads and resistive circuits in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 60715, using either the integrated snap-on clips or optional screw fixing — standard panel integration for this class. The 24 VDC coil draws 10 A at rated voltage, and the contactor is rated for 1,000 switching cycles per hour under AC-1, AC-2, AC-3, and AC-3e duty, dropping to 300 cycles per hour for the heavier AC-4 category (–,). That AC-3 rating is the one that matters for standard three-phase motor starting — the contactor can handle frequent starts across a shift without derating. Operating temperature spans -25 to +60 °C, with storage from -55 to +80 °C. The mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward or backward — useful when the panel layout forces an unusual orientation.
Sourcing & Lifecycle
The auxiliary switch block is included, and the main contact wiring accepts solid or stranded copper from 1 to 10 mm², with dual-wire capability for smaller gauges. Terminal type is screw-type on the magnet coil.
Integration & Mounting
The S0 frame measures 45 mm wide, 85 mm high, and 97 mm deep. Clearance requirements: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm to the side. The arcing time is 10 ms, and the opening time at AC is 4–16 ms. These clearances are tight enough for dense panel layouts but leave room for wiring access. Mechanical life is rated at 10,000,000 operating cycles typical. The contactor carries an auxiliary switch — good for status feedback to a PLC or for interlocking in a reversing starter circuit.