Auxiliary switch block for SIRIUS contactor relays
The Siemens 3RH2911-1GA22-ZW97 is a front-mounted auxiliary switch block for the SIRIUS contactor relay family, delivering 2 normally-open and 2 normally-closed contacts in a physically coded housing that mates only with 3RH2140 and 3RH2440 contactor relays per EN 50011. Rated at 10 A, it carries 10 A at 24 V and derates to 6 A at 230 V or 250 V, with AC-15 switching capability at 690 V rated 1 A — so it handles pilot-duty loads like PLC inputs and relay coils across a 24 V to 690 V control range. Snap-on mounting clips directly to the contactor relay without tools, occupying 36 mm width on the DIN rail — a standard footprint for panel integration.
Contact reliability and switching life
Mechanical service life is rated at 10 million switching cycles typical, with contact reliability specified as one faulty switching per 100 million operations at 17 V, 1 mA — a dry-circuit spec that matters when switching low-energy signals from sensors or PLC outputs. Insulation voltage is 690 V at pollution degree 3, surge voltage resistance 6 kV, and front protection IP20 — adequate for enclosed control panels where the switch is behind a door.
Termination and wiring
Screw-type terminals accept 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²) with core end processing, or AWG 2x (20–16) and 2x (18–14). The switch block includes two instantaneous contacts (the 2 NO + 2 NC set) with no leading or lagging contact — all four poles switch simultaneously, so it suits straightforward status feedback or interlocking without timing tricks.