What it is and what it does
The Siemens 3RH2140-1BF40-0AA6 is a SIRIUS auxiliary contactor in the S00 frame size, designed to switch control signals and auxiliary loads in motor starter and contactor assemblies. It carries four normally-open instantaneous contacts, rated for switching at 110 V DC coil voltage. Mounting is via screw or snap-on onto a 35 mm standard mounting rail, with a footprint of 45 mm wide, 57.5 mm high, and 73 mm deep. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, giving panel layout flexibility.
Switching capacity and contact ratings
The contacts handle 10 A at 24 V and 230 V rated values, 4.7 A at 60 V, 3 A at 110 V and 400 V, 1.2 A at 220 V, 0.5 A at 440 V, 2 A at 500 V, 0.26 A at 600 V, and 1 A at 690 V. This voltage-dependent derating means the 3RH2140-1BF40-0AA6 is suited for mixed-voltage control panels where the same contact block switches both 24 V DC sensor signals and 230 V AC pilot devices. The magnet coil draws 4 W during closing and 4 W holding, both at DC, so the coil power budget is flat — no inrush spike to size a power supply around. Mechanical service life is rated at 30,000,000 operating cycles typical, with a maximum switching frequency of 10,000 operations per hour at AC.
Environmental and compliance
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Pollution degree 3 means it tolerates conductive pollution or dry non-conductive pollution that becomes conductive through condensation — standard for industrial control panels not in a sealed cleanroom.
Panel integration and wiring
Terminals accept solid or stranded conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm². Clearance distances are 10 mm upwards, forwards, and downwards, and 6 mm at the side — these are the minimum air gaps to maintain for the rated insulation. The S00 frame size matches the Siemens 3RT2 and 3RT1 contactor series, so this auxiliary contactor block mounts directly alongside or on top of those contactors using the same DIN rail or screw fixing. The 4 NO contact configuration is typical for adding extra interlock or status feedback contacts to a motor starter.