{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2045-1KB40-1AA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2045-1KB40-1AA0","canonicalUrl":"https://aoctrl.com/siemens/3RT2045-1KB40-1AA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2045-1KB40-1AA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS S3 coupling contactor, 3RT2045-1KB40-1AA0, 24 VDC coil, screw terminals, 70 x 140 x 152 mm, snap-on 35 mm DIN rail.","salesMarkdown":"## SIRIUS S3 coupling contactor, 24 VDC coil ## DC switching capacity and coil draw Rated coil voltage is 24 VDC; inrush current peaks at 2.7 A. The contactor switches DC loads at 10 A at 24 V rated value, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V. That 10 A at 24 VDC is the headline figure for most control-circuit isolation or DC-motor switching applications — the derating curve above 24 V is steep, so verify your load voltage against the table before specifying. ## Switching frequency per duty class Maximum switching rates are duty-dependent: 900 cycles/hour at AC-1 (resistive), 400/h at AC-2 (slip-ring motors), 1 000/h at AC-3 (squirrel-cage motors — start only), 300/h at AC-4 (plugging/inching), and 1 000/h at AC-3e (enhanced AC-3). The AC-3 and AC-3e rates of 1 000/h are the highest here, but that's for starting duty only — if your application includes inching or reversing, the AC-4 limit of 300/h is the governing number. ## Auxiliary contacts and mechanical endurance An auxiliary switch is fitted. Arcing time runs 10–20 ms; opening time at DC is 38–57 ms. Shock resistance is 16.3 g at 5 ms and 10 g at 10 ms — enough for most industrial panels but worth checking if the contactor is mounted near a large hammer-mill or press. Main circuit terminals accept solid 2.5–16 mm² or stranded 6–70 mm². Auxiliary terminals take 2x (0.5–1.5 mm²) solid or stranded, or 2x (0.75–2.5 mm²). That 70 mm² stranded capacity on the main terminals is generous for a size S3 frame — it can handle the larger cable gauges typical of 30–40 A motor circuits without needing a terminal reducer. ## Environmental range and clearances The 20 mm forward clearance is the one that catches panel layouts — if the enclosure door or busbars are tight, that dimension decides fit.","metaTitle":"Siemens 3RT2045-1KB40-1AA0 SIRIUS S3 Coupling Contactor, 24","metaDescription":"Siemens SIRIUS 3RT2045-1KB40-1AA0 coupling contactor, size S3, 24 VDC coil. Active production. Screw and snap-on 35 mm DIN rail. Rated 10 A at 24 VDC. 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":"3RT2045-1KB40-1AA0","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, screw terminal, size: S3, suitable for PLC outputs, upright mounting position","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Screw-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":"standing, on horizontal mounting surface","Size Of Contactor":"S3","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 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":"screw-type 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":"Screw-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), 2x (18 ... 14)","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), 2x (0.75 ... 2.5 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 %","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":"$201.93","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=629800&mlfb=3RT2045-1KB40-1AA0"},"ai":{"faq":[{"question":"Where can I buy 3RT2045-1KB40-1AA0 and get current pricing?","answer":"This part is 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 price and lead time."},{"question":"What are the key ratings for 3RT2045-1KB40-1AA0?","answer":"24 VDC coil with 10 A switching at 24 VDC. Main terminals accept up to 70 mm² stranded. Switching rate up to 1 000 cycles/hour in AC-3 duty. Mechanical endurance is 10 million operations typical."},{"question":"What compliance documentation does Siemens provide for 3RT2045-1KB40-1AA0?","answer":"As a SIRIUS product line contactor, it carries the standard Siemens industrial compliance package including RoHS and REACH declarations. The product brand is SIRIUS; documentation is available through the Siemens Industry Online Support portal."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2045-1KB40-1AA0","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/3RT2045-1KB40-1AA0 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}}