Solid-State-Compatible 2 NC Auxiliary Switch for SIRIUS Contactors
The 3RH2911-4NF02 is a front-mounted auxiliary switch designed for the SIRIUS 3RT2 contactor and 3RH2 contactor relay series. It provides two normally-closed (NC) contacts that are solid-state compatible, meaning the low-energy switching circuit (5 V, 1 mA) is rated for one incorrect switching operation per 100 million cycles — critical when the switch feeds a PLC input or a solid-state logic input that cannot tolerate contact oxidation. Rated insulation voltage is 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV. This positions the switch for 400 V and 690 V industrial control panels where transient overvoltages from motor starts or nearby lightning are common.
Mounting and Connection — Snap-On Front Fit, Ring Lug Terminals
Snap-on mounting to the front of contactors in sizes S00, S0, S2, and S3 — no tools needed for installation, and the switch sits flush against the contactor face, adding 36 mm width and 43.7 mm depth to the assembly. The ring terminal lug connection accepts crimp ring lugs for secure, vibration-resistant wiring in the auxiliary and control circuits. Mechanical service life is 5,000,000 operating cycles typical, matching the endurance of the base contactor in high-cycle applications like conveyor systems or packaging machinery.
Sourcing and Lifecycle — Current Production, Available to Order
The mirror contact feature per IEC 60947-4-1 is present when the switch is used with 3RT2.2/3/4 contactors — this is a safety-relevant attribute for applications requiring welded-contact detection in motor starter circuits.