The Siemens 3RT2526-2BF40 is a SIRIUS S0-size contactor with a 110 V AC coil terminated via spring-type terminals. It mounts on a 35 mm DIN rail per DIN EN 50022 using screw or snap-on fastening, and the S0 frame keeps the footprint compact at 61 mm wide by 102 mm tall by 107 mm deep — a tight fit for a panel with 6 mm side clearance to adjacent devices. The coil holds at 110 V rated value, with a pickup threshold of 0.8 x rated (88 V) and a full-scale overvoltage limit of 1.1 x rated (121 V). Mechanical life is typical 10 million operations; the AC-1 switching rate reaches 5,000 cycles per hour, dropping to 1,000 cycles per hour at maximum AC-1 load.
Zero clearance is allowed upwards, forwards, and backwards; only the sides need 6 mm. The spring-type terminals accept 2x (0.5 to 2.5 mm²) solid or stranded conductors — no screw torque to verify, just strip and insert.
The integrated auxiliary switch is rated for DC switching at 24 V (10 A), 48 V (2 A), 60 V (2 A), 110 V (1 A), 125 V (0.9 A), 220 V (0.3 A), and 600 V (0.1 A). AC switching at 230 V carries 10 A, at 400 V 3 A, at 440 V 1 A, at 500 V 2 A, and at 690 V 1 A. Arcing time is 10 to 10 ms; DC switching dropout takes 15 to 18 ms.