The Siemens 3RH1140-1AR10 is a SIRIUS auxiliary contactor in size S00, carrying four normally-open instantaneous contacts rated for 10 A in AC-12 duty. That AC-12 rating — resistive loads at unity power factor — is the figure that governs its use in control circuits feeding PLC outputs, relay coils, and indicator lamps. The 4 NO configuration means it adds four isolated signal paths without introducing any delayed or make-before-break switching, so it slots into standard interlocking and feedback circuits where timing must stay deterministic.
Panel fit and mounting
At 45 mm wide, 57.5 mm tall, and 72 mm deep, this contactor occupies a single modular DIN-rail pitch — standard for a size S00 block. The fastening method accepts both screw fixing and snap-on mounting, so it can be clipped directly onto a DIN rail or bolted to a backplate in panels where rail space is tight. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward or backward, which helps when routing wires in a crowded enclosure.
Contact ratings and switching capability
Beyond the headline 10 A AC-12 rating, the contacts carry defined currents at other common control voltages: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V. The surge voltage resistance is rated at 6 kV, which aligns with basic insulation coordination for industrial control panels. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — a meaningful figure for low-energy signal circuits where oxide films on silver contacts can cause intermittent failures.
Wiring and termination
Terminals accept solid conductors in three size ranges: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and 2x 4 mm². For AWG, the equivalent is 2x (20 to 16), 2x (18 to 14), and 1x 12. The degree of pollution is rated 3, meaning the contactor is designed for environments with conductive or dry non-conductive pollution — typical of most industrial control panels not in clean-room conditions.