What It Is and Where It Fits
The Siemens 3RT2025-2XB40-0LA2 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads and resistive loads in industrial control panels. It carries a 24 VDC coil with spring-type terminals, and mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The S0 size means it occupies a 45 mm width on the rail, with a depth of 107 mm and height of 102 mm — a compact footprint for a contactor rated for AC-3 duty cycles up to 1,000 operations per hour.
Key Ratings and What They Mean for Fit
The 24 VDC coil draws a 3 A inrush peak, with a hold-in range that drops out below roughly 18 V — standard for DC-operated contactors. The spring-type terminals on the coil accept solid conductors from 1 to 10 mm² and stranded from 0.5 to 2.5 mm², which covers most control-circuit wiring in panel builds. The main contacts are rated for AC-3 switching at up to 1,000 cycles per hour, and for AC-4 (plugging/reversing) at 300 cycles per hour — the derating for severe duty is built in. The contactor's mechanical life is typical at 10 million operations, so it suits high-cycle applications like conveyor or pump control where the contactor sees frequent switching.
Mounting and Integration Details
Mounting position is flexible: the contactor can be rotated ±180° on a vertical surface, and tilted forward/backward by ±22.5° on that same surface. Clearances required: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the sides. The auxiliary switch is included, so no separate add-on block is needed for basic signaling. The spring-type terminals on the coil reduce wiring time compared to screw terminals — strip to 8 mm, insert, and the cage holds. For the main contacts, the solid wire range is 2x (1 to 10 mm²), which handles motor feeds up to the contactor's rating.