What the ratings mean for fit
The 3RT2025-2KF40 is a SIRIUS coupling contactor in the S0 frame size, designed for switching auxiliary or control circuits rather than main motor loads. Its 110 V coil pulls in at 70% of rated voltage per the initial-value spec, and the spring-type terminals accept solid or stranded conductors from 1 to 10 mm² — no screwdriver needed for termination, which speeds panel wiring and reduces torque-verification steps during commissioning. The contactor is rated for 1 000 switching cycles per hour under AC-1, AC-2, AC-3, and AC-3e duty, and 300 cycles per hour under AC-4. That means it handles frequent on-off cycles in a control scheme — think interposing relays or PLC-driven contactor banks — without exceeding thermal limits. The arcing time sits at 10 ms, consistent with a DC-coil dropout time of 19 to 21 ms, so the circuit opens cleanly within one mains half-cycle. Mounting is screw-and-snap-on to 35 mm DIN rail per DIN EN 60715. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so it fits into tight enclosures or non-standard panel layouts. Clearance requirements: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm at the side — these are the minimum air gaps to maintain rated insulation and cooling.
Auxiliary contact ratings — what they actually switch
The auxiliary contact set (no auxiliary switch fitted as standard per) is rated for DC switching at several voltage levels: 10 A at 24 V, 2 A at 48 V, 2 A at 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. These are the make/break capacities for resistive DC loads — useful when the contactor drives a DC solenoid, a signal lamp, or a PLC input. The 3 A at 400 V rating also covers AC-1 resistive switching at that voltage level.