What it is and where it fits
The Siemens SIRIUS 3RH1911-1FB22-ZW98 is an auxiliary switch block designed for use with SIRIUS contactor relays and power contactors. It snaps onto a 35 mm DIN rail and provides additional switching contacts for control circuits. The block carries one normally-open (NO) contact, one normally-closed (NC) contact, and one instantaneous contact, wired via screw-type terminals that accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or ferruled stranded wire, or 2x (20 to 16) or 2x (18 to 14) AWG. Front protection is IP20, meaning it's touch-safe but not sealed against moisture — suitable for dry indoor panel environments. The operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C.
What the ratings mean for your circuit
The maximum continuous current is 10 A, but the actual rating depends on the voltage and duty. For DC control circuits, the rated operational current at 24 V is 10 A, dropping to 6 A at 125 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — the arc-extinction limit governs the lower currents at higher DC voltages. For AC-15 inductive loads (typical for solenoid valves and contactor coils), the rated current at 24 V is 10 A, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. The AC-15 rating at 690 V is 1 A. These are the numbers to use when sizing for coil loads. The insulation voltage is rated at 690 V AC with pollution degree 3, and surge voltage resistance is 6 kV — adequate for standard industrial control panels. Mechanical service life is 10 million switching cycles, with contact reliability of 1 faulty switching per 100 million operations at 17 V, 1 mA.