What it is and what it does
The Siemens 3RT6025-1BF40 is a SIRIUS power contactor in the Size S0 frame, with a 110 V rated coil. It switches motor loads in control panels and is rated for AC-3 and AC-3e duty up to 690 V maximum. At 400 V and 60 °C it handles 23 kW motor power; at 690 V and 60 °C that climbs to 40 kW. Mounting is via screw fixing or snap-on onto 35 mm DIN rail per DIN EN 50022. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward or backward — useful when fitting into crowded enclosures.
Key ratings and what they mean for fit
The AC-3 rated voltage maximum of 690 V means this contactor can switch three-phase induction motors on a 690 V line — common in European industrial networks. The AC-3e rating at the same voltage covers the newer energy-efficient motor standard, so it's forward-compatible with IE3/IE4 motor replacements. Operating temperature range of -25 to +60 °C covers most panel environments; storage range of -55 to +80 °C matters for warehousing and shipping in extreme climates. Pollution degree 3 means it's rated for conductive pollution typical in industrial control rooms — no special derating needed for dusty or humid conditions. Main and auxiliary/control circuits both use screw-type terminals. The main terminals accept 2x (0.5 to 1.5 mm²) solid/stranded or 2x (0.75 to 2.5 mm²), with AWG equivalents of 2x (16 to 12) or 2x (14 to 8). Minimum permissible conductor at 40 °C and 60 °C is 10 mm² — important when sizing for full rated current without terminal overheating. Mechanical life is typical 10 million operations. Electrical life varies by duty: AC-1 and AC-3 maximum 1,000 cycles per hour, AC-4 maximum 300 cycles per hour, and DC switching at 1,500 cycles per hour. The AC-4 figure is the one to watch for plugging or inching applications — it's the limiting duty cycle.
Integration notes
Side-by-side mounting is permitted without derating — useful for multi-contactor motor starter assemblies. The Size S0 frame (45 mm wide, 85 mm tall, 107 mm deep) fits standard DIN-rail enclosures. The 110 V coil draws 6 A at 24 V rated value, 1 A at 110 V, 0.3 A at 220 V, 10 A at 230 V, 3 A at 400 V, and 1 A at 690 V — these are the pickup/hold currents for sizing the control transformer.