What it is and what it does
The Siemens 3RH2911-2HA13-0KT0 is a front-mounted auxiliary switch block for the SIRIUS family, designed to snap onto 3RT2 power contactors and 3RH2 contactor relays. It provides one normally-open and three normally-closed auxiliary contacts, wired out to terminals 31/32, 41/42, 51/52, and 63/64 respectively. Rated for a maximum of 10 A, the contacts carry AC-15 pilot-duty loads at 690 V up to 1 A, and switch DC control circuits at various voltages — 6 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, and 0.26 A at 600 V. The AC-15 rating at 690 V (1 A) is the relevant figure for switching contactor coils or solenoid valves in a 400/690 V panel. Contact reliability is specified at one faulty switching per 100 million operations at 17 V, 1 mA — a dry-circuit capability that matters for PLC-level signals where oxide films on silver contacts can cause intermittent opens. Mechanical life is rated for 10 million switching cycles typical.
Mounting and wiring
Snap-on mounting to the contactor or relay front face — no tools needed, and the 36 mm width matches the standard SIRIUS contactor footprint, so it occupies the same DIN-rail slot as the base device. The spring-loaded terminals accept 2x (0.5 to 1.5 mm²) with ferruled ends, or 2x (0.5 to 2.5 mm²) without core-end processing; AWG equivalents are 2x (20 to 14). IP20 protection on the front means the terminals are finger-safe inside the enclosure but not sealed against dust ingress — standard for control-panel auxiliary blocks, not for washdown areas.
Ratings in context
The 6 kV surge voltage resistance (rated value) and insulation voltage of 690 V at pollution degree 3 mean this block is suitable for 400 V line-to-line panels with a 600 V impulse-withstand requirement — typical for IEC 60947-5-1 auxiliary contact applications. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The storage limit governs handling and shipping, not running conditions.