{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-3BD40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-3BD40","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-3BD40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3BD40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, Size S3, order code 3RT1045-3BD40, rated 45 kW at 500 V AC-3, screw-type terminals, snap-on DIN rail mounting.","salesMarkdown":"## SIRIUS Power Contactor, Size S3 — 3RT1045-3BD40 The Siemens 3RT1045-3BD40 is a SIRIUS power contactor in Size S3, rated for 45 kW at 500 V in AC-3 duty — the standard motor-switching category per IEC 60947-4-1. That 45 kW figure at 500 V is the load it can switch under full motor starting conditions; at 690 V the same contactor carries 21.1 kW. AC-3 switching means it makes and breaks a motor load at full locked-rotor current, so the 45 kW rating governs the motor nameplate it can handle. Mounting is screw-and-snap-on onto 35 mm or 75 mm standard mounting rail — the 75 mm option is unusual for a Size S3 frame and gives panel builders flexibility when rail spacing is non-standard. ## Switching Performance and Mechanical Life Electrical life depends on duty: at AC-3 (motor start/run) the maximum switching rate is 1 000 operations per hour; at AC-4 (plugging, inching, reversing) it drops to 300 operations per hour. ## Environmental Range and Terminal Capacity Solid wire connections accept 2x (0.25 to 2.5 mm²) for control circuits; stranded main conductors take 2x (10 to 50 mm²). The auxiliary contact block (if fitted) shares the same coil suppression — verify free-wheel diode polarity before energising inductive loads downstream.","metaTitle":"Siemens 3RT1045-3BD40 SIRIUS Power Contactor, Size S3, 500V","metaDescription":"Siemens 3RT1045-3BD40 SIRIUS power contactor, Size S3, rated 45 kW at 500 V AC-3. Screw terminals, snap-on DIN rail. Active production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"152 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"70 mm","at DC":"14 ... 20 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","Arcing Time":"10 ... 15 ms","Rated Value":"42 V","On The Front":"IP20; IP20 on the front with cover / box terminal","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of The Terminal":"IP00","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","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm and 75 mm standard mounting rail","Full-Scale Value":"1.1","Size Of Contactor":"S3","Solid Or Stranded":"2x (2.5 ... 16 mm²)","Product Brand Name":"SIRIUS","Degree Of Pollution":"3","Product Designation":"power contactor","at 24 V rated value":"10 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 220 V rated value":"0.3 A","at 230 V rated value":"6 A","at 400 V rated value":"3 A","at 500 V rated value":"45 kW","at 690 V rated value":"21.1 kW","Side-By-Side Mounting":"Yes","at 1000 V rated value":"37 W","For Main Current Circuit":"screw-type terminals","at AC-2 at 400 V rated value":"37 kW","at AC-4 at 400 V rated value":"66 A","Substance Prohibitance (Date)":"05/01/2012","at 40 °C minimum permissible":"50 mm²","at 60 °C minimum permissible":"35 mm²","Insulation Voltage Rated Value":"1 000 V","at 230 V at 60 °C rated value":"38 kW","at 690 V at 60 °C rated value":"114 kW","at 1000 V at 60 °C rated value":"82 W","at AWG cables for main contacts":"2x (10 ... 1/0)","For Auxiliary And Control Circuit":"spring-loaded terminals","With Type Of Assignment 2 Required":"fuse gL/gG: 160 A","closing power of magnet coil at DC":"15 W","holding power of magnet coil at DC":"15 W","Surge Voltage Resistance Rated Value":"6 kV","With Type Of Coordination 1 Required":"fuse gL/gG: 250 A","at AWG cables for auxiliary contacts":"2x (24 ... 14)","operational current at AC-12 maximum":"10 A","number of NC contacts for main contacts":"0","number of NO contacts for main contacts":"3","reference code according to IEC 81346-2":"Q","Finely Stranded With Core End Processing":"2x (0.25 ... 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)","Thermal Short-Time Current Limited To 10 S":"760 A","Finely Stranded Without Core End Processing":"2x (0.25 ... 2.5 mm²)","Type Of Voltage Of The Control Supply Voltage":"DC","Required Spacing For Grounded Parts At The Side":"6 mm","contact rating of auxiliary contacts according to UL":"A600 / Q600","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","number of NC contacts for auxiliary contacts instantaneous contact":"0","number of NO contacts for auxiliary contacts instantaneous contact":"0","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000"}},"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=328974&mlfb=3RT1045-3BD40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3BD40/alternatives.json"},"ai":{"faq":[{"question":"What is the 3RT1045-3BD40's depth?","answer":"The depth is 152 mm, with a width of 70 mm and height of 146 mm — a Size S3 frame that fits standard motor control centre buckets."},{"question":"Will the 3RT1045-3BD40 drop into a panel specified for the 3RT1044-1FB46?","answer":"Both are SIRIUS Size S3 contactors with the same 70 mm width and 146 mm height, so the footprint and DIN-rail mounting are identical. The depth may differ — the 3RT1045-3BD40 is 152 mm deep. Check the 3RT1044-1FB46 depth against your enclosure clearance before swapping. Terminal configurations (screw-type on this unit) should be verified against the existing wiring."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-3BD40","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/3RT1045-3BD40 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}}