Siemens 3RT2526-1BW40 SIRIUS Contactor — Size S0, 24 V DC Coil
It carries a 24 V DC coil and is rated to switch 10 A at 24 V DC, with a broader DC switching capability across voltages up to 690 V — for instance, 2 A at 48 V, 1 A at 110 V, and 0.3 A at 220 V. The AC-1 resistive load rating reaches 10 A at 230 V and 3 A at 400 V, making it suitable for smaller motor and heater circuits within its contactor class.
The S0 footprint measures 85 mm high by 61 mm wide by 107 mm deep, so it fits standard panel layouts. Clearance requirements are minimal — 6 mm at the sides, zero mm upwards, forwards, and backwards. The screw-type coil terminals accept 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded wire, which covers typical control wiring.
Switching Performance and Ratings
Rated for 5 000 switching operations per hour on AC loads, and 1 000 per hour at AC-1 maximum. DC switching has an arcing time of 10 ms and a dropout delay of 15 to 18 ms. The coil hold-in voltage is 0.8 of rated value, dropout at 1.1 of rated value.