The Siemens 3RH1140-1AE00 is a SIRIUS auxiliary contactor — a compact switching block that mirrors the state of a main contactor or provides isolated signal feedback in a control circuit. It carries four normally-open instantaneous contacts and is sized for the S00 contactor frame, meaning it mounts directly alongside or on top of S00 power contactors like the 3RT1015 or 3RT1016 series without extra adapters.
The headline rating is 10 A at 24 V, which is also the maximum operating current under AC-12 duty — that's the resistive-load switching category for control circuits. So this contactor handles typical PLC output loads, relay coils, indicator lamps, and small solenoid valves without derating. For inductive loads like contactor coils or small motors, the switching capacity drops: at 230 V it's rated 6 A, at 400 V it's 3 A, and at 690 V it's 1 A. Those are the numbers to use when sizing for motor control or transformer circuits.