The Siemens 3RH2122-1KJ80 is a SIRIUS coupling relay designed for switching auxiliary circuits in control panels. It carries two instantaneous normally-open contacts, each rated for 10 A at 24 V and 10 A at 230 V, with a 72 V DC coil that includes an integrated suppressor diode. The coil draws 2.8 W at closing.
The 10 A rating at 24 V and at 230 V tells you the contacts handle resistive loads up to that current across a wide voltage range — useful for pilot lamps, solenoid valves, and small contactor coils. At 60 V the rating drops to 4.7 A, at 110 V to 3 A, and at 400 V to 3 A; the curve reflects the AC-1 duty class typical for auxiliary relays. The mechanical life of 30 000 000 operations means this relay is built for high-cycle applications like pick-and-place lines or conveyor interlocks where the contacts cycle many times per shift.
The relay measures 45 mm wide, 57.5 mm high, and 73 mm deep — the S00 footprint. Wire connection accepts 2 x (0.5 to 1.5 mm²), 2 x (0.75 to 2.5 mm²), or 2 x 4 mm² solid or stranded conductors.