Front-Mounted Auxiliary Switch for 3RT2 / 3RH2 Contactors
The 3RH2911-1LA20-ZX95 is a SIRIUS auxiliary switch block that mounts on the front of Siemens 3RT2 contactors and 3RH2 contactor relays, adding two normally-open (NO) auxiliary contacts (terminals 73/74 and 83/84) with screw-type connections. Rated for a maximum of 10 A, the switch provides a mechanical service life of 10 million switching cycles typical, making it suitable for high-cycle applications like conveyor interlocks or valve position feedback. Snap-on mounting onto the contactor front simplifies panel assembly — no additional hardware or DIN-rail space is consumed beyond the contactor footprint.
Switching Capacity Across Voltage Levels
The auxiliary contacts deliver 6 A at 24 V, 125 V, 230 V, and 250 V, but derate to 3 A at 400 V and 0.3 A at 220 V — the voltage-dependent current limits reflect the arc-quenching capability of the contact gap. At AC-15 duty (inductive loads typical of contactor coils and solenoid valves), the switch is rated 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 — these are the values to use for sizing in control circuits. Insulation voltage is rated 690 V at pollution degree 3, with a surge voltage resistance of 6 kV, ensuring reliable isolation in industrial panels with mixed-voltage wiring.