The Siemens 3RH2911-1DC11-0KW0 is a lateral-mounted auxiliary switch block from the SIRIUS family, carrying 1 normally-open and 1 normally-closed contact. The NO contact is leading (closes first on pickup), the NC contact is lagging (opens first on dropout), which gives you sequenced switching for interlocking or logic feedback in a motor starter or contactor relay circuit.
Switching ratings — what they mean on the line
The block is rated for 10 A maximum, but the real-world limit depends on your voltage and load type. At 24 V DC it switches 6 A; at 60 V DC it drops to 2 A; at 220 V DC you're down to 0.3 A. For AC-15 inductive loads at 690 V it's rated 1 A. These aren't just numbers — they tell you where this block will hold up and where it won't. If you're switching a 24 V DC pilot light or a PLC input, the 6 A rating gives you plenty of headroom. If you're trying to break a 220 V DC solenoid at 0.5 A, the 0.3 A rating says you're pushing it — expect contact wear. The contacts are rated for 10 million mechanical switching cycles typical, and the contact reliability spec says fewer than 1 faulty switching per 100 million operations at 17 V, 1 mA. That's a solid number for dry-signal switching — think PLC inputs or safety relay feedback where a bad contact means a nuisance fault.
Mounting and wiring in the panel
Snap-on mounting clips directly to the contactor. The 10 mm width keeps the assembly tight. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire.