What it is and where it fits
The Siemens 3RH1131-1AM20 is a SIRIUS auxiliary contactor in the Size S00 frame, carrying three normally-open instantaneous contacts and no delayed, lagging, or leading switching contacts. It is designed for control-circuit isolation and signal feedback in motor starter assemblies, contactor banks, and PLC output interposing — the three NO contacts handle the logic-level switching while the main contactor handles the load. Rated 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V, the contactor's switching capacity drops predictably as voltage rises — at 690 V it is rated 1 A. The 6 kV surge voltage resistance (rated value) means it withstands transient overvoltages common in industrial control panels without flashover. Mechanical service life is typical 30 million operations, and contact reliability is specified as one incorrect switching operation per 100 million switching operations at 17 V, 1 mA — a dry-circuit rating that matters for PLC input signals where oxide films on silver contacts can cause intermittent opens.
Mounting and integration
Mounts via screw and snap-on onto DIN rail. The Size S00 footprint — 45 mm wide, 57.5 mm tall, 72 mm deep — fits standard control-panel layouts. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, giving flexibility in tight enclosures. Terminal capacity accepts solid conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or 2x 4 mm². IP20 protection on the front means the terminals are finger-safe but the contactor is intended for installation inside a rated enclosure. Pollution degree 3 per IEC 60947-1 — suitable for industrial environments with conductive pollution or occasional condensation. Operating temperature range -25 to +60 °C; storage and transport range -55 to +80 °C.
Lifecycle and compliance
Rated control supply voltage is 50 Hz (0.8–1.1 range) and 60 Hz (0.85–1.1 range) at 208 V — the coil accepts both 50 and 60 Hz supplies within those tolerance bands, so it works on either mains frequency without a hardware change.