The Siemens SIRIUS 3RH2911-2GA40-ZW97 is a front-mounted auxiliary switch block for contactor relays, specifically the 3RH2140 and 3RH2440 frames per EN 50011. It provides four normally-open instantaneous contacts — terminals 53/54, 63/64, 73/74, and 83/84 — in a single 36 mm wide package that snaps onto a DIN rail. The spring-loaded terminals accept 2x (0.5 to 2.5 mm²) without ferrules or 2x (0.5 to 1.5 mm²) with core-end processing, and AWG 20 to 14 for the auxiliary circuit.
The AC-15 switching capacity at 690 V is 1 A — that's the inductive load rating for solenoid or contactor coils. For resistive loads at 24 V, the rated operational current is 10 A; at 230/250 V AC it's 6 A. The surge voltage withstand is 6 kV, and contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — meaning it handles low-level PLC signals without intermittent opens.
The 36 mm width occupies one standard modular device position. Depth is 47.7 mm, height 41.5 mm. The IP20 front protection means it's suitable for enclosed control panels where no washdown or dust ingress is expected.