What it is and what it does
The Siemens 3RH1122-2AV60 is a SIRIUS S00-size auxiliary contactor — basically the relay that tells the main contactor when to pull in or drops out a status signal. It carries four contact sets (two instantaneous make, two break, no leading or delayed switching) and mounts via screw or snap-on onto a DIN rail. Out here in the grease, that snap-on feature means you can swap it without pulling the whole panel apart, which saves a good half-hour on a line-down call.
Key ratings and what they mean for your panel
Rated 10 A at AC-12 (resistive load at 24 V) and 6 A at AC-15 at 230 V — that's the switching capacity for solenoid valves or contactor coils. At 400 V it's 3 A, at 500 V it's 2 A, and at 690 V it holds 1 A. The mechanical life is spec'd at 30 million operations, and contact reliability is one failure per 100 million operations at 17 V, 1 mA — that low-level switching matters when you're reading dry contacts from a PLC input card. Pollution degree 3 means it's happy in a typical industrial panel with some dust and humidity, not just a clean control room.
Mounting and environment
Size S00 footprint: 45 mm wide, 60 mm tall, 73 mm deep. Screw terminals accept 2x 0.25 to 2.5 mm² solid or 24–14 AWG stranded. The front carries IP20 protection — fine inside an enclosure, not for washdown. Shock-rated at 10g for 5 ms and 5g for 10 ms, so it'll survive a forklift bump to the panel. Operating temperature range is -25 to +60 °C; storage and transport go from -55 to +80 °C. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, which gives you flexibility when the backplate is already crowded.