What it is and what it does
The Siemens 3RH1911-1FC22 is a SIRIUS auxiliary switch block designed for use with contactor relays and power contactors. It provides 2 normally open and 2 normally closed contacts (2 NO + 2 NC), wired via screw-type terminals, and snaps onto the contactor without tools. Contact ratings vary by voltage and duty: the maximum continuous current is 10 A, with specific ratings at 24 V (6 A), 60 V (2 A), 110 V (1 A), 125 V (6 A), 220 V (0.3 A), 230 V (6 A), 250 V (6 A), and 400 V (3 A). For AC-15 inductive loads, ratings are 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. Mechanical service life is rated at 10 million switching cycles typical, with contact reliability of one faulty switching per 100 million operations at 17 V, 1 mA. The block is rated for surge voltage resistance of 6 kV and insulation voltage of 690 V AC at pollution degree 3.
Lifecycle and sourcing reality
For BOM lines that require the exact 3RH1911-1FC22, we source it to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time. If you are open to the successor, the 3RH2911-1FC22 is a direct drop-in replacement with the same footprint and wiring.
Panel integration and mounting
Snap-on mounting onto the contactor — no DIN rail required. The block measures 36.5 mm wide, 37.5 mm high, and 41.5 mm deep, fitting the S00 frame size of SIRIUS contactors. 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. Front protection is IP20, suitable for enclosed panels. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The leading and lagging contact arrangement is 2 each, with no instantaneous contacts.