What It Is and What It Does
The Siemens 3RH1911-2FB11 is a SIRIUS auxiliary switch block designed for use with contactor relays and power contactors in the Size S00 footprint. It provides one normally open (NO) and one normally closed (NC) contact, rated for a maximum of 10 A, with switching capacities specified across a range of voltages — for example, 6 A at 24 V, 6 A at 230 V, and 3 A at 400 V. The spring-loaded terminals accept conductors without core end processing up to 2x 2.5 mm², making for quick wiring in panel builds.
Integration Notes
Snap-on mounting onto Size S00 contactors or contactor relays means it clips directly onto the device front without tools. The 36.5 mm width and 46 mm depth keep the assembly within the standard DIN-rail envelope. Spring-loaded terminals reduce wiring time compared to screw terminals, and the IP20 front protection is standard for enclosed panel use.
Key Ratings in Context
The 10 A maximum rating applies across the contact set, but the actual switching capacity depends on the circuit voltage and load type. For AC-15 control-circuit duty at 690 V, the rated value is 1 A. The mechanical service life is 10 million switching cycles typical, and contact reliability is specified as one faulty switching per 100 million operations at 17 V, 5 mA — useful for low-energy signal circuits where oxide films can cause intermittent opens.