Snap-on auxiliary switch for S00 contactors
The Siemens SIRIUS 3RH1911-1FA22-ZW98 is an auxiliary switch block designed for snapping onto the front of S00-size contactor relays and power contactors. It adds two instantaneous NO contacts to the base device, expanding the control circuit without increasing the panel footprint. Rated 6 A at both 24 V and 230 V, with a maximum AC-12 operational current of 10 A. The AC-15 rating at 690 V is 1 A, covering typical control-circuit loads like PLC inputs and relay coils. The switch carries a mirror contact feature per IEC 60947-4-1 when used with 3RT1 contactors, meaning the NO contact cannot remain closed if the main contactor welds — a safety requirement for drives and motor starters where welded contacts must not go undetected. Dimensions are 41.5 mm deep by 36.5 mm wide by 37.5 mm high, fitting the standard S00 envelope. Snap-on mounting onto the contactor front means no DIN rail space is consumed — useful when the panel is already dense.
Contact ratings and switching capability
The auxiliary contacts are rated for a range of control voltages: 6 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V and 250 V, and 3 A at 400 V. These cover common AC and DC control circuits found in industrial panels. For DC switching, ratings include 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. The contact reliability specification — one faulty switching per 100 million operations at 17 V, 1 mA — confirms suitability for low-energy signal circuits like PLC inputs. Mechanical service life is 10 million operating cycles typical, matching the contactor it mounts on. Surge voltage resistance is rated at 6 kV, adequate for standard industrial environments without additional suppression.
Installation and wiring
Snaps onto the front of S00 contactors — no tools, no DIN rail. The IP20 front protection means the terminals are finger-safe once the panel door is closed, but the switch itself is not rated for washdown environments. Terminals accept 2 x (0.5 to 1.5 mm²) solid or stranded, or 2 x (0.75 to 2.5 mm²) with ferruled ends. AWG equivalents are 2 x (20 to 16) and 2 x (18 to 14). Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The switch is rated for use with contactor relays and power contactors — not as a standalone device.
Lifecycle and compliance
Substance prohibitance date is July 1, 2006, indicating RoHS compliance from that date forward. The switch carries mirror contact certification per IEC 60947-4-1 when paired with 3RT1 contactors.