{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2122-2LF40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2122-2LF40","canonicalUrl":"https://aoctrl.com/siemens/3RH2122-2LF40","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2LF40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS coupling relay, 3RH2122-2LF40, size S00, 2 NO contacts, 10 A at 24 V, screw and snap-on 35 mm DIN rail.","salesMarkdown":"The Siemens 3RH2122-2LF40 is a SIRIUS coupling relay for switching auxiliary circuits — a compact, size S00 device that mounts on 35 mm DIN rail via screw or snap-on fastening. It carries 2 normally-open instantaneous contacts and is rated for 10 A at both 24 V and 230 V, making it a straightforward interface between a control signal and a higher-power auxiliary load. The 10 A rating at 24 V and 230 V covers most pilot-duty and control-transformer loads in a panel. The contactor size S00 (73 mm deep, 45 mm wide, 70 mm high) is the standard footprint for this class of auxiliary relay — it fits alongside S00 contactors in the same DIN-rail zone without crowding. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt, which helps when routing wires in a dense cabinet. Coil closing power is 2.8 W at DC, a reasonable draw for a 24 VDC control loop. The built-in varistor surge suppressor handles back-EMF from the coil, so you do not need an external flyback diode on the PLC output card. The screw terminals accept 2x 0.5 to 4 mm² solid or stranded wire. Clearance: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm to the side for arc flash and wiring access. The size S00 profile keeps it shallow enough for shallow enclosures.","metaTitle":"Siemens 3RH2122-2LF40 SIRIUS Coupling Relay, 10 A at 24 V","metaDescription":"Siemens SIRIUS 3RH2122-2LF40 coupling relay for switching auxiliary circuits. 2 NO contacts, 10 A at 24 V, 10 A at 230 V. Screw and snap-on 35 mm DIN rail. Current lifecycle.","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":"7 ... 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":"110 V","Initial Value":"0.7","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail","Full-Scale Value":"1.25","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":"2.8 W","holding power of magnet coil at DC":"2.8 W","Surge Voltage Resistance Rated Value":"6 kV","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","for AWG cables for auxiliary contacts":"2x (20 ... 12)","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":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=55907&mlfb=3RH2122-2LF40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2LF40/alternatives.json"},"ai":{"faq":[{"question":"What are the key dimensions for panel fit?","answer":"Depth is 73 mm, width is 45 mm, height is 70 mm. It mounts on 35 mm DIN rail with 10 mm clearance required upwards, forwards, and downwards, and 6 mm to the side."},{"question":"What is the switching capacity at typical control voltages?","answer":"It is rated 10 A at 24 V and 10 A at 230 V. At 110 V it carries 3 A, and at 400 V it carries 3 A — derate accordingly for higher voltages."},{"question":"Does it include surge suppression?","answer":"Yes, it comes with a built-in varistor surge suppressor across the coil, so no external diode or RC snubber is needed for inductive kickback."},{"question":"What compliance documentation is available?","answer":"The part carries a substance prohibition date of 10/01/2009, which aligns with RoHS compliance. The SIRIUS series typically includes UL, CSA, and CE declarations — confirm with the manufacturer for specific cert numbers."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2122-2LF40","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/3RH2122-2LF40 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}}