Front-Mount Auxiliary Block for 3RH2 and 3RT2 Contactors
The 3RH2911-1FA22-0MA0 is a front-mounted auxiliary switch block from the Siemens SIRIUS family, designed to snap onto 3RH2 contactor relays and 3RT2 power contactors — one spare part covers both families in the panel. The contact arrangement is 2 normally-open and 2 normally-closed instantaneous contacts, wired via screw-type terminals that accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) conductors per clamp — or 2x (20 to 16) and 2x (18 to 14) AWG. The 10 A maximum thermal current (Ith) sets the continuous current ceiling for the auxiliary contacts, with the 24 V rated value also at 10 A — this block handles pilot-duty and signal-level loads, not motor power. The AC-15 rating at 690 V is 1 A, confirming suitability for solenoid and contactor coil switching in 400 V and 690 V control circuits.
Ratings That Govern the Real Circuit
Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — this dry-circuit performance figure is the one that matters when the block feeds a PLC input or a safety relay, not just a pilot light. The mechanical service life of 10 million operating cycles typical means the switch block outlasts the contactor it rides on under normal duty. The insulation voltage is 690 V at pollution degree 3 — the block is rated for industrial enclosures where conductive dust or condensation may be present, so no additional creepage derating is required in a standard IP54 panel. Surge voltage resistance is 6 kV, matching the impulse withstand level for 400 V distribution systems. IP20 on the front means the screw terminals are finger-safe when the panel door is open, but the block must be installed inside an enclosure — it is not rated for open-machine washdown service.
Active Production — Sourced Per BOM
This part carries an active lifecycle status from Siemens — it is current-production, not a legacy or discontinued item. There is no official successor or cross-reference because none is needed; the 3RH2911-1FA22-0MA0 is the standard front-mount auxiliary block for the SIRIUS 3RH2 and 3RT2 families. Sourced and quoted to order against the BOM quantity through independent distribution. Snap-on DIN rail mounting (35 mm per EN 60715) means no tools are needed for installation or removal — a consideration for panel builders who need to reconfigure control circuits without disturbing the main contactor wiring.