The Siemens SIRIUS 3RH1911-1GA22-ZW97 is a 4-pole auxiliary switch block with 2 normally open and 2 normally closed contacts, intended for use with contactor relays and power contactors. It snaps onto the contactor without tools, adding auxiliary contact capacity for feedback or interlock circuits.
Contact ratings and what they mean for your circuit
The contacts are rated for a maximum of 10 A, but the actual switching capacity depends on the voltage. At 24 V DC the contacts handle 6 A; at 60 V DC it drops to 2 A; at 110 V DC it's 1 A; at 220 V DC it's 0.3 A. For AC-15 duty at 690 V the rating is 1 A. These are the numbers that matter when you're sizing the block for a specific control voltage — don't assume the 10 A max applies across the board. The block also carries a separate set of rated operational currents for the contactor relay application: 10 A at 24 V, 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. Use the set that matches your circuit type.
Mounting and wiring
It snaps onto the contactor — no screws needed for the mechanical attachment. The auxiliary and control circuit connections use screw-type terminals, accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core-end processing, or 2x (20 to 16) and 2x (18 to 14) AWG. The front face is IP20, so it's protected against finger contact in the panel.
Durability and reliability
Mechanical service life is rated at 10 million switching cycles typical. Contact reliability is specified as 1 faulty switching per 100 million operations at 17 V and 1 mA — that's the low-level signal reliability you need for PLC inputs or safety circuits where oxide films on dry contacts can cause intermittent faults.
Insulation coordination
Rated surge voltage resistance is 6 kV, and insulation voltage at AC with pollution degree 3 is 690 V.