{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2122-2KF40-0LA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2122-2KF40-0LA0","canonicalUrl":"https://aoctrl.com/siemens/3RH2122-2KF40-0LA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2122-2KF40-0LA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS, auxiliary contactor, size S00, 3RH2122-2KF40-0LA0, 2 NO instantaneous contacts, 110 VDC coil with suppressor diode, screw and snap-on mounting on 35 mm DIN rail, 45 mm width.","salesMarkdown":"The Siemens 3RH2122-2KF40-0LA0 is a SIRIUS auxiliary contactor in size S00, carrying 2 normally-open instantaneous contacts and a 110 VDC coil with an integrated suppressor diode. The contact ratings are given at multiple voltage levels, and the right one to look at depends on your load voltage. At 24 V the contacts are rated 10 A, at 110 V it's 3 A, at 230 V it's 10 A, and at 400 V it's 3 A. These are thermal current ratings for the contact block — they tell you the continuous current the contacts can carry at that voltage level. For DC switching, the ratings drop significantly: 4.7 A at 60 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. That steep derating curve is typical for DC because DC arcs are harder to extinguish than AC arcs. If you're switching a DC control circuit, size the load against the DC column, not the AC one. ## Coil and Switching Dynamics The 110 VDC coil draws 13 W closing power and includes a suppressor diode. Pickup voltage is 0.7 x rated; dropout is 1.25 x rated. Mechanical life is 30 million operations, switching frequency 10,000 1/h for AC, DC on-time 7 to 20 ms. ## Mounting and Environmental Specs Operating temperature range is -40 to +70 °C, storage is -55 to +80 °C, with 10% minimum relative humidity.","metaTitle":"Siemens 3RH2122-2KF40-0LA0 SIRIUS Auxiliary Contactor, 110 V","metaDescription":"Siemens SIRIUS 3RH2122-2KF40-0LA0 auxiliary contactor, size S00, 2 NO contacts, 110 VDC coil with suppressor diode. 45 mm wide, screw & snap-on DIN rail. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"116 mm","Width":"45 mm","at AC":"10 000 1/h","at DC":"7 ... 20 ms","title":"3RH2122-2KF40-0LA0","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","description":"Contactor relay for railway, 2 NO + 1 NC, 110 V DC, 0.7... 1.25* US, with integrated suppressor diode, Size S00, Spring-type terminal suitable for PLC outputs","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 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":"Auxiliary contactor","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":"suppressor diode","Product Extension Auxiliary Switch":"Yes","closing power of magnet coil at DC":"13 W","holding power of magnet coil at DC":"4 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":"1","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":"21","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","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","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":"$36.83","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/49b5cd39548384abd19880a57d6c7da9.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=294101&mlfb=3RH2122-2KF40-0LA0"},"ai":{"faq":[{"question":"What is the closest functional second-source to 3RH2122-2KF40-0LA0?","answer":"The 3RH2122-1BW40 is a direct peer in the same SIRIUS auxiliary contactor family, size S00, also with 2 NO contacts. The key difference is the coil voltage: the -1BW40 uses a different coil rating, so verify your control voltage before substituting. The mechanical footprint and terminal layout are identical — it will drop into the same DIN-rail slot without rewiring the load side, but the coil supply must match."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2122-2KF40-0LA0","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/3RH2122-2KF40-0LA0 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}