{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2045-3KB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2045-3KB40","canonicalUrl":"https://aoctrl.com/siemens/3RT2045-3KB40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2045-3KB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT2045-3KB40 coupling contactor, S3 frame, 24 V DC coil, spring-type terminals, 152 x 70 x 140 mm, DIN rail mount.","salesMarkdown":"The 3RT2045-3KB40 is a SIRIUS coupling contactor in the S3 frame size, designed for switching auxiliary circuits or smaller loads where a standard power contactor would be oversized. ## Panel fit and wiring — the numbers that matter The spring-type coil terminals accept the same range without needing a screwdriver — a time-saver on repetitive panel builds. Switching rates vary by duty class: 900 ops/h in AC-1 (resistive), 400 in AC-2 (slip-ring motors), 1,000 in AC-3 (squirrel-cage motors — the most common), and 300 in AC-4 (plugging/inching). The AC-3e rating also lists 1,000 ops/h — matching the standard AC-3 figure for energy-efficient motor starters. Arcing time is 10 to 20 ms; mechanical response at AC is 16.3 g / 5 ms and 10 g / 10 ms, while DC dropout takes 38 to 57 ms. These timing numbers matter for interlock circuits where the contactor must open before a downstream device re-energises. ## Sourcing and lifecycle — active production, no obsolescence worry Lifecycle stage is listed as current — Siemens continues to manufacture this order code. The 3RT2045-3KB40 is a standard SIRIUS catalog item, stocked broadly across distribution.","metaTitle":"Siemens 3RT2045-3KB40 SIRIUS Coupling Contactor, 24 V Coil","metaDescription":"Siemens 3RT2045-3KB40 SIRIUS coupling contactor, 24 V DC coil, S3 frame size, spring-type terminals, 10 A holding current. Active production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"152 mm","Solid":"2.5 ... 16 mm²","Width":"70 mm","at AC":"16.3g / 5 ms, 10.g / 10 ms","at DC":"38 ... 57 ms","title":"3RT2045-3KB40","Height":"140 mm","Upwards":"10 mm","Forwards":"20 mm","Stranded":"6 ... 70 mm²","Downwards":"10 mm","Arcing Time":"10 ... 20 ms","At The Side":"10 mm","Rated Value":"24 V","description":"power contactor, AC-3e/AC-3, 80 A, 37 kW / 400 V, 3-pole, 24 V DC, 0.8-1.2* Us, with integrated varistor, auxiliary contacts: 1 NO + 1 NC, integrated varistor, main circuit: screw terminal, control and auxiliary circuit: spring-loaded terminal, size: S3, suitable for PLC outputs","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Spring-type terminals","at AC-1 maximum":"900 1/h","at AC-2 maximum":"400 1/h","at AC-3 maximum":"1 000 1/h","at AC-4 maximum":"300 1/h","lifecycle_stage":"current","Auxiliary Switch":"Yes","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715","Full-Scale Value":"1.2","at AC-3e maximum":"1 000 1/h","For Main Contacts":"10 ... 2","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":"S3","Solid Or Stranded":"2x (0.5 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Inrush Current Peak":"2.7 A","Product Designation":"Coupling contactor","at 24 V rated value":"10 A","at 48 V rated value":"2 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 125 V rated value":"0.9 A","at 220 V rated value":"0.3 A","at 230 V rated value":"15 hp","at 400 V rated value":"3 A","at 440 V rated value":"0.8 A","at 480 V rated value":"77 A","at 500 V rated value":"2 A","at 600 V rated value":"62 A","at 690 V rated value":"1 A","Side-By-Side Mounting":"Yes","at 1000 V rated value":"37 kW","For Auxiliary Contacts":"20 ... 14","For Main Current Circuit":"screw-type terminals","at 110/120 V rated value":"7.5 hp","at 200/208 V rated value":"25 hp","at 220/230 V rated value":"30 hp","at 460/480 V rated value":"60 hp","at 575/600 V rated value":"60 hp","Locked-Rotor Current Peak":"2.1 A","Relative Humidity Minimum":"10 %","Holding Current Mean Value":"40 mA","Of Main Circuit Rated Value":"8 kV","Safety-Related Switching On":"No","at AC-3 rated value maximum":"1 000 V","at AC in hot operating state":"15.9 W","at AC-2 at 400 V rated value":"37 kW","at AC-3e rated value maximum":"1 000 V","at AC-4 at 400 V rated value":"66 A","safety-related switching OFF":"Yes","Substance Prohibitance (Date)":"03/01/2017","Design Of The Surge Suppressor":"with varistor","Duration Of Inrush Current Peak":"50 µs","Locked-Rotor Current Mean Value":"0.9 A","Duration Of Locked-Rotor Current":"150 ms","Of Auxiliary Circuit Rated Value":"6 kV","at AC-5a up to 690 V rated value":"110 A","at AC-5b up to 400 V rated value":"80 A","For Auxiliary And Control Circuit":"spring-loaded terminals","Function Module For Communication":"No","With Type Of Assignment 2 Required":"gG: 160A (690V,100kA), aM: 80A (690V,100kA), BS88: 125A (415V,80kA)","Without Load Current Share Typical":"0.9 W","closing power of magnet coil at DC":"25 W","holding power of magnet coil at DC":"0.9 W","At Contactor For Auxiliary Contacts":"Spring-type terminals","With Type Of Coordination 1 Required":"gG: 250 A (690 V, 100 kA), aM: 160 A (690 V, 100 kA), BS88: 200 A (415 V, 80 kA)","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"5.3 W","for AWG cables for auxiliary contacts":"2x (20 ... 16)","number of NO contacts for main contacts":"3","reference code according to IEC 81346-2":"Q","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes","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 %","Type Of Voltage Of The Control Supply Voltage":"DC","Limited To 1 S Switching At Zero Current Maximum":"1 500 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 5 S Switching At Zero Current Maximum":"1 186 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 10 S Switching At Zero Current Maximum":"851 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 30 S Switching At Zero Current Maximum":"538 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 60 S Switching At Zero Current Maximum":"423 A; Use minimum cross-section acc. to AC-1 rated value","contact rating of auxiliary contacts according to UL":"A600 / P600","Of Main Circuit With Degree Of Pollution 3 Rated Value":"1 000 V","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","Of Auxiliary Circuit With Degree Of Pollution 3 Rated Value":"690 V","For Short-Circuit Protection Of The Auxiliary Switch Required":"gG: 10 A (500 V, 1 kA)","minimum cross-section in main circuit at maximum AC-1 rated value":"50 mm²","number of NC contacts for auxiliary contacts instantaneous contact":"1","number of NO contacts for auxiliary contacts instantaneous contact":"1","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$191.77","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/7d28fa7380658c541019ac8751bc4da6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=629830&mlfb=3RT2045-3KB40"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2045-3KB40","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/3RT2045-3KB40 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}}