The Siemens 3RH2122-1BP40 is a SIRIUS auxiliary contactor in frame size S00, carrying two normally-open instantaneous contacts. It is designed for screw and snap-on mounting onto 35 mm DIN rail, making it a direct fit for standard control-panel enclosures. The 24 VDC coil draws 4 W for both closing and holding, so there is no inrush spike to budget for on the DC supply.
Switching Capacity by Voltage
Rated operational current is specified across the voltage range: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 10 A at 230 V, 3 A at 400 V, 0.5 A at 440 V, 2 A at 500 V, 0.26 A at 600 V, and 1 A at 690 V. The 230 V figure matches the 24 V rating, which is unusual — verify the load type against the duty class in your application. The 10 A at 230 V is the headline figure for general switching.
Mounting and Clearance
Snap-on to 35 mm DIN rail or screw-mount directly. Dimensions are 45 mm wide, 57.5 mm tall, 73 mm deep — the S00 footprint that fits alongside SIRIUS contactors and overload relays in a compact row. Minimum clearances to adjacent components: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so panel layout is flexible.
Wiring and Environment
Terminals accept 2 x (0.5 to 1.5 mm²), 2 x (0.75 to 2.5 mm²), or 2 x 4 mm² solid or stranded wire. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Pollution degree 3 (industrial environment). Relative humidity minimum 10 %. RoHS compliance date is 10/01/2009, covering the EU RoHS scope.