Part identity and function
The Siemens 3RH1122-2KV40-1AA0 is a SIRIUS auxiliary contactor in frame size S00, designed for switching control and signal circuits rather than main motor loads. It carries 2 normally-open and 2 normally-closed instantaneous contacts, with no make-before-break or delayed switching elements. The coil is rated 36 VDC with an integrated varistor surge suppressor, drawing 11 W during pickup and 4 W holding. This built-in suppression means you don't need an external flyback diode or RC snubber across the coil — the varistor handles the inductive kick, which simplifies panel wiring and reduces component count.
Switching capacity and contact reliability
The auxiliary contacts are rated for switching at multiple voltage levels: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. These are the thermal continuous current ratings at each voltage — the actual making/breaking capacity for inductive loads will be lower, so size the contacts to the inrush of whatever pilot device (relay, PLC input, solenoid valve) they drive. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — a dry-circuit rating that matters for PLC inputs and low-level signal switching where oxide films on silver contacts can cause intermittent opens. The mechanical life is 30 million operations typical, which is standard for this S00 frame size.
Mounting and integration
Mounts via screw or snap-on onto a DIN rail, with a standing position on a horizontal surface. The S00 footprint is 45 mm wide, 60 mm high, and 73 mm deep — compact enough for dense control panels. The front face carries IP20 protection, so it's suitable for enclosed panels where no one touches live parts. Terminals accept 2x solid conductors from 0.25 to 2.5 mm². Pollution degree 3 means it's rated for industrial environments with conductive contamination — no special coating needed for most cabinet conditions.
Environmental and compliance
Operating temperature range is -25 to +60 °C, with storage and transport from -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms — sufficient for most industrial machinery but not for extreme vibration environments like crushers or off-road vehicles. The substance prohibitance date of 07/01/2006 aligns with RoHS compliance. Surge voltage resistance is rated at 6 kV, which covers basic impulse withstand for 400 VAC systems (overvoltage category III). The coil's closing power of 11 W and holding power of 4 W are within the range a typical 36 VDC power supply can handle — just check the supply's inrush rating if multiple contactors pick up simultaneously.