Siemens 3RH1911-1FA11 Contactor Auxiliary Contact

Siemens 3RH1911-1FA11 is a snap-on auxiliary contact block for Sirius-size S00 contactors, delivering a compact 2‑pole auxiliary circuit with 1 normally open (NO) and 1 normally closed (NC) contact. The 11 configuration confirms the NO/NC pairing, and the module uses screw terminals for wiring, making it compatible with auxiliary and motor contactors in the Sirius family. Key ratings include an insulation voltage of 690 V and a surge resistance of 6 kV, with electrical endurance around 200,000 switching cycles at AC-15 with 230 V and a mechanical life typically up to 10,000,000 switching cycles. The auxiliary contacts are specified for reliability, described as 1 faulty switching per 100 million cycles in typical data sheets. Siemens lists 3RH1911-1FA11 as a no-longer-available accessory, with 3RH2911-1HA11 identified as the recommended successor. This block provides a discrete NO/NC signal derived from the main contactor’s status, useful for signaling to PLCs, interlocks, or safety circuits in automation installations.