The Siemens 3RT2526-2BW40 is a SIRIUS S0-frame contactor with spring-type coil terminals. The S0 frame size means this contactor is sized for moderate motor loads and auxiliary switching duties common in conveyor, pump, and fan circuits. The spring-type coil termination eliminates the need for screwdriver torque control on the coil wiring — a time-saver during panel build and a reliability gain against vibration loosening.
That covers most enclosure orientations without derating. This tight clearance envelope means you can pack contactors side-by-side without worrying about arc flash between phases — the 10 ms arcing time is contained within the S0 housing.
Auxiliary contact ratings — switching capability across the voltage range
The built-in auxiliary switch handles 10 A at 24 V, 10 A at 230 V, and 3 A at 400 V, with ratings down to 0.1 A at 600 V. This covers PLC-level signals up to small pilot-duty loads. The solid/stranded wire capacity is 2x (0.5... 2.5 mm²), which matches standard control wiring practice. Switching frequency is rated at 5,000 cycles per hour for AC operation, with a maximum of 1,000 cycles per hour at AC-1 resistive load. DC switching timing is 15...18 ms; arcing time is 10 ms. These numbers are relevant for high-cycle applications like indexing conveyors or rapid-reversing drives.
Thermal limits and lifecycle status
The 60 °C ceiling is adequate for most ventilated enclosures, but if this contactor sits near a furnace or hot-strip mill stand, you'll want to verify the ambient at the mounting location stays under that limit. The storage range confirms it can survive cold warehouses.