{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2122-2WB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2122-2WB40","canonicalUrl":"https://aoctrl.com/siemens/3RH2122-2WB40","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2WB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS coupling relay for switching auxiliary circuits, order code 3RH2122-2WB40, 24 V DC coil, 10 A rated at 24 V, size S00, screw and snap-on mounting on 35 mm DIN rail.","salesMarkdown":"## SIRIUS coupling relay for auxiliary circuits The Siemens 3RH2122-2WB40 is a SIRIUS coupling relay designed for switching auxiliary circuits — the kind of signal-level or control load that follows a contactor or PLC output in a panel. Its 24 V DC coil draws a closing power of 1.6 W, so it sits lightly on a 24 V supply without requiring a separate power supply derating. The size S00 footprint — 45 mm wide, 73 mm deep, 70 mm high — fits the compact slot in a SIRIUS contactor assembly or standalone on a DIN rail. ## Switching ratings and surge suppression The relay carries a built-in varistor surge suppressor across the coil, so no external snubber is needed for inductive loads switched by the coil circuit. Rated operational currents at various voltages: 10 A at 24 V, 10 A at 230 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V — the curve drops with voltage, as expected for an AC-rated auxiliary contact block. At DC voltages, the 24 V rating is 10 A, 60 V is 4.7 A, 110 V is 3 A, 220 V is 1.2 A, 440 V is 0.5 A, 600 V is 0.26 A. Mechanical life is typical 30 million operations.","metaTitle":"Siemens 3RH2122-2WB40 SIRIUS Coupling Relay, 24 V Coil, 10 A","metaDescription":"Siemens SIRIUS 3RH2122-2WB40 coupling relay for auxiliary circuits. 24 V DC coil, 10 A rated at 24 V. Screw and snap-on 35 mm DIN rail. Current lifecycle stage. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"73 mm","Width":"45 mm","at AC":"10 000 1/h","at DC":"5 ... 20 ms","Height":"70 mm","Upwards":"10 mm","Forwards":"10 mm","Downwards":"10 mm","Arcing Time":"10 ... 15 ms","At The Side":"6 mm","Rated Value":"24 V","Initial Value":"0.85","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-25 ... +50 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail","Full-Scale Value":"1.85","Mounting Position":"+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface","Size Of Contactor":"S00","Solid Or Stranded":"2x (0,5 ... 4 mm²)","Product Brand Name":"SIRIUS","Degree Of Pollution":"3","Product Designation":"Coupling relay for switching auxiliary circuits","at 24 V rated value":"10 A","at 60 V rated value":"4.7 A","Of Contactor Typical":"30 000 000","at 110 V rated value":"3 A","at 220 V rated value":"1.2 A","at 230 V rated value":"10 A","at 400 V rated value":"3 A","at 440 V rated value":"0.5 A","at 500 V rated value":"2 A","at 600 V rated value":"0.26 A","at 690 V rated value":"1 A","Instantaneous Contact":"2","Relative Humidity Minimum":"10 %","Substance Prohibitance (Date)":"10/01/2009","Design Of The Surge Suppressor":"with varistor","Product Extension Auxiliary Switch":"No","closing power of magnet coil at DC":"1.6 W","holding power of magnet coil at DC":"1.6 W","Surge Voltage Resistance Rated Value":"6 kV","at AWG cables for auxiliary contacts":"2x (20 ... 12)","operating frequency at DC-12 maximum":"1 000 1/h","operating frequency at DC-13 maximum":"1 000 1/h","operational current at AC-12 maximum":"10 A","reference code according to IEC 81346-2":"K","Finely Stranded With Core End Processing":"2x (0.5 ... 2.5 mm²)","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","with low demand rate according to SN 31920":"40 %","Finely Stranded Without Core End Processing":"2x (0.5 ... 2.5 mm²)","with high demand rate according to SN 31920":"73 %","number of NC contacts for auxiliary contacts":"2","number of NO contacts for auxiliary contacts":"2","Type Of Voltage Of The Control Supply Voltage":"DC","contact rating of auxiliary contacts according to UL":"A600 / Q600","Identification Number And Letter For Switching Elements":"22 E","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Type Of Electrical Connection For Auxiliary And Control Circuit":"spring-loaded terminals","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Design Of The Fuse Link For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","design of the miniature circuit breaker for short-circuit protection of the auxiliary circuit up to 230 V":"C characteristic: 6 A; 0.4 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/66609db1681f4163cff013becd9f2b1e.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=424629&mlfb=3RH2122-2WB40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2WB40/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RH2122-2WB40 and get a price?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm quote."},{"question":"What is the closest functional second-source for 3RH2122-2WB40?","answer":"The 3RH2122-1WB40 is the closest functional peer — same SIRIUS size S00, same auxiliary contact configuration, same 24 V coil. The -2WB40 includes a built-in varistor surge suppressor; the -1WB40 does not. Otherwise they share the same mounting footprint and ratings."},{"question":"Will 3RH2122-2WB40 drop into a panel specified for 3RH2122-1WB40?","answer":"Yes — same size S00 footprint, same mounting, same terminal arrangement. The only difference is the built-in varistor on the -2WB40. No rewiring needed."},{"question":"What compliance documentation does Siemens provide for 3RH2122-2WB40?","answer":"The part carries a substance prohibition date of 10/01/2009, indicating RoHS compliance. Standard Siemens documentation includes the declaration of conformity and product manual. Specific UL, CSA, or IEC certifications should be verified against the nameplate or Siemens support."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2122-2WB40","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RH2122-2WB40 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}