Siemens SIRIUS Auxiliary Contact Block 3NO + 1NC Front Mounting Screw Terminal – 3RH2911-1HA31

The Siemens SIRIUS 3RH2911-1HA31 is a four-pole auxiliary switch block that snaps onto the front of a 3RT2 contactor or 3RH2 contactor relay, adding three normally-open and one normally-closed contact for interlocking, signalling and control logic. Positively driven operation to IEC 60947-5-1 means the contacts are mechanically tied to the main contactor state—essential where the auxiliary contact is relied on for safe interlocking. Terminal designation follows EN 50012. Features 3 NO + 1 NC instantaneous contacts (contact sequence 1 NC, 1 NO, 1 NO, 1 NO) Front-mounting: snaps onto the base unit without additional rail space Fits 3RT2 contactors sizes S00 to S3 and 3RH2 contactor relays Screw terminals accepting 0.5–2.5 mm² Rated insulation voltage 690 V, thermal current 10 A 10 million operating cycles mechanical endurance Positively driven operation per IEC 60947-5-1; mirror contact per IEC 60947-4-1 Specifications Siemens order number 3RH2911-1HA31 Product designation Auxiliary switch, on the front, 3 NO + 1 NC, screw terminal Product family SIRIUS Innovations Contact configuration 3 NO + 1 NC (4 poles, all instantaneous) Contact sequence 1 NC, 1 NO, 1 NO, 1 NO Mounting Front-mounting (snap-on) Terminal designation per EN 50012 Connection type Screw terminals Conductor cross-section 0.5–2.5 mm², solid or stranded Rated insulation voltage (Ui) 690 V at pollution degree 3 Rated impulse withstand voltage (Uimp) 6 kV Thermal current (Ith) 10 A AC-15 rated current 6 A at 24 V / 6 A at 230 V / 3 A at 400 V / 1 A at 690 V DC-13 rated current 6 A at 24 V / 2 A at 60 V / 1 A at 110 V / 0.3 A at 220 V / 0.3 A at 250 V Suitable for 3RT2.1, 3RT2.2, 3RT2.3, 3RT2.4 contactors (sizes S00, S0, S2, S3) and 3RH2 contactor relays Mechanical endurance 10,000,000 operating cycles Electrical endurance approx. 200,000 operating cycles (AC-15, 230 V) Dimensions (H × W × D) 37.5 × 36 × 43.7 mm Degree of protection IP20 Ambient temperature –25 to +60 °C in operation; –55 to +80 °C storage Standards IEC 60947-5-1, IEC 60947-4-1 Please note Size S00 restriction: per Siemens, on size S00 this block can be mounted to EN 50012 only on base units which have no integrated NC contact. Please check your base unit before ordering. This is the SIRIUS Innovations generation accessory, for 3RT2 / 3RH2 base units. The predecessor for older 3RT1 / 3RH1 base units is 3RH1911-1HA31. For the spring-loaded (push-in) terminal version of the same contact complement, order 3RH2911-2HA31. Contact us if you need the ring-terminal variant.