The Siemens 3RH2911-1GA22-ZW98 is a SIRIUS auxiliary switch block designed exclusively for the 3RH2140 and 3RH2440 contactor relay frames. It provides 2 normally-open and 2 normally-closed contacts arranged per EN 50011, with screw-type terminals for the auxiliary and control circuits. The physical coding on the housing prevents accidental mounting on incompatible relay bases — it only clicks onto those two specific relay models.
Rated for 10 A maximum, with AC-15 switching capacity at 24 V also rated at 10 A. That means it handles the inrush of contactor coils and solenoid valves in a control panel without welding the contacts. At higher voltages the current capability drops — 6 A at 230 V, 3 A at 400 V, and 0.5 A at 440 V — so verify your load's voltage before committing the BOM line.
Rated for 10 million mechanical switching cycles typical, so it outlasts most contactor relays in cyclic service.
Snap-on mounting to the relay base — no DIN rail footprint of its own, it rides on the contactor relay. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16) and 2x (18 to 14) AWG.