{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2122-2XB40-2LA2","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2122-2XB40-2LA2","canonicalUrl":"https://aoctrl.com/siemens/3RH2122-2XB40-2LA2","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2XB40-2LA2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS contactor relay, 3RH2122-2XB40-2LA2, railway-rated, 24-34 VDC coil, varistor suppression, 2 NO instantaneous contacts, size S00, screw and snap-on 35 mm DIN rail.","salesMarkdown":"This relay carries 2 normally-open instantaneous contacts, and the interrupting capacity varies sharply with voltage — something to watch if you're switching mixed AC loads. At 230 V rated value it handles 10 A, at 400 V rated value it drops to 3 A, and at 690 V rated value it's down to 1 A. The DC side is more restrictive: 10 A at 24 V, 4.7 A at 60 V, and only 0.26 A at 600 V. Those numbers tell you this is a control relay, not a power contactor — use it to pilot larger contactors or signal lamps, not to switch motor loads directly. It's size S00, which is the smallest Siemens contactor footprint — 45 mm wide, 70 mm tall, 73 mm deep. That 45 mm width means it takes up one standard 45 mm module slot on the rail. You can pack these in a panel without much breathing room.","metaTitle":"Siemens 3RH2122-2XB40-2LA2 SIRIUS Contactor Relay, Railway,","metaDescription":"Siemens SIRIUS 3RH2122-2XB40-2LA2 contactor relay for railway applications. 24-34 VDC coil with varistor, 2 NO contacts, S00 size, screw/snap-on 35 mm DIN rail. Available 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 DC":"25 ... 45 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 ... 34 V","Initial Value":"0.7","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-40 ... +70 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail","Full-Scale Value":"1.25","Mounting Position":"hanging, on horizontal mounting surface","Size Of Contactor":"S00","Solid Or Stranded":"2x (0,5 ... 4 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Contactor relay for railway applications","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","Side-By-Side Mounting":"Yes","Relative Humidity Minimum":"10 %","Substance Prohibitance (Date)":"10/01/2009","Design Of The Surge Suppressor":"Varistor","Product Extension Auxiliary Switch":"Yes","closing power of magnet coil at DC":"4 W","holding power of magnet coil at DC":"0.95 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","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","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","AWG number as coded connectable conductor cross section for auxiliary contacts":"20 ... 12","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000","Design Of The Fuse Link For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","residual current of the electronics for control with signal <0> at DC at 24 V maximum permissible":"10 mA","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=765424&mlfb=3RH2122-2XB40-2LA2","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2XB40-2LA2/alternatives.json"},"ai":{"faq":[{"question":"What is the 3RH2122-2XB40-2LA2 used for?","answer":"It's a Siemens SIRIUS contactor relay designed for railway applications — switching control signals, piloting larger contactors, or driving indication lamps in rolling stock and trackside cabinets. The 24-34 VDC coil with built-in varistor handles the noisy DC supply typical of traction batteries."},{"question":"How do I get pricing and availability for 3RH2122-2XB40-2LA2?","answer":"Submit an RFQ through this listing. Availability and current pricing are confirmed at quote time through our independent distribution network — we source to order against your BOM line."},{"question":"What's the difference between 3RH2122-2XB40-2LA2 and 3RH2122-1BA40?","answer":"The -2XB40-2LA2 includes a built-in varistor surge suppressor across the coil, while the -1BA40 variant does not. Both are size S00 with 2 NO contacts and the same 24-34 VDC coil range. If your railway panel already has external suppression, the -1BA40 saves cost; if not, the -2LA2 version saves a panel component."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2122-2XB40-2LA2","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/3RH2122-2XB40-2LA2 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}}