Auxiliary contactor for control-circuit switching
The Siemens 3RH1140-1AH10 is a SIRIUS auxiliary contactor in size S00, carrying four normally-open instantaneous contacts for switching control circuits up to 10 A in AC-12 duty (resistive loads at 24 V). Rated operational current drops with voltage: 6 A at 230 V, 3 A at 400 V, 1 A at 690 V — so the 10 A figure applies only at 24 V, not across the full range.
Rated switching capacity and contact reliability
AC-12 rating of 10 A is the headline number, but the contactor also carries 1 A at 110 V and 0.27 A at 220 V for DC control circuits — the DC curve is much lower than the AC curve, so don't assume the AC rating transfers. Contact reliability is specified at one incorrect switching operation per 100 million cycles at 17 V, 1 mA — a dry-circuit rating that matters for PLC inputs or low-level signal switching where oxide films can block conduction.
Shock resistance of 10g / 5 ms and 5g / 10 ms covers most industrial panel vibration; the mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so it fits tight enclosures without derating.
Wiring and terminal data
Screw terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid/stranded; AWG equivalents are 2x (20–16), 2x (18–14), and 1x 12. Surge voltage resistance is 6 kV, which coordinates with standard 400 V motor circuits and upstream Type 2 surge arrestors.