{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-3AC20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-3AC20","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-3AC20","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3AC20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, size S3, 3RT1045-3AC20, 45 kW at 500 V AC-3, 24 V 50/60 Hz coil, screw-type terminals, snap-on DIN rail.","salesMarkdown":"The Siemens 3RT1045-3AC20 is a SIRIUS power contactor in size S3, rated for switching motor loads up to 45 kW at 500 V in AC-3 duty, or 21.1 kW at 690 V. The 24 V 50/60 Hz coil draws the listed holding power. Screw-type terminals on the main circuit accept 2x (10... 50 mm²) stranded or 2x (0.25... 2.5 mm²) solid control wiring. The front carries IP20 protection with the cover or box terminal fitted; the terminal body itself is IP00, meaning the wiring compartment is open to the panel environment — plan for enclosure-level sealing. Dimensions are 146 mm high, 70 mm wide, 139 mm deep — a compact S3 footprint that fits standard panel layouts without surprises. ## Duty ratings and mechanical life Rated for 1 000 switching operations per hour in AC-3 duty, 900 in AC-1, 400 in AC-2, and 300 in AC-4. Arcing time runs 10... 15 ms; the total break time at AC is 10... 25 ms.","metaTitle":"Siemens 3RT1045-3AC20 SIRIUS Power Contactor, 45 kW at 500 V","metaDescription":"Siemens 3RT1045-3AC20 SIRIUS power contactor, size S3, 45 kW at 500 V AC-3, 24 V 50/60 Hz coil. Screw terminals, snap-on DIN rail. Available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"139 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"70 mm","at AC":"10 ... 25 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","at 50 Hz":"0.8 ... 1.1","at 60 Hz":"0.85 ... 1.1","Arcing Time":"10 ... 15 ms","On The Front":"IP20; IP20 on the front with cover / box terminal","1 Rated Value":"50 Hz","2 Rated Value":"60 Hz","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","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 50 Hz rated value":"24 V","at 500 V rated value":"45 kW","at 60 Hz rated value":"24 V","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","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)","apparent holding power of magnet coil at AC":"27 VA","apparent pick-up power of magnet coil at AC":"298 VA","Type Of Voltage Of The Control Supply Voltage":"AC","Required Spacing For Grounded Parts At The Side":"6 mm","contact rating of auxiliary contacts according to UL":"A600 / Q600","Inductive Power Factor With Closing Power Of The Coil":"0.7","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Inductive Power Factor With The Holding Power Of The Coil":"0.29","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=144216&mlfb=3RT1045-3AC20","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3AC20/alternatives.json"},"ai":{"faq":[{"question":"What is 3RT1045-3AC20 used for?","answer":"It is a power contactor for switching three-phase motor loads up to 45 kW at 500 V AC-3, or resistive loads up to the AC-1 rating. Common in conveyor, pump, fan, and compressor control panels."},{"question":"Where can I buy 3RT1045-3AC20?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"Will 3RT1045-3AC20 drop into a panel specified around 3RT1044-1FB46 without rewiring?","answer":"Both are SIRIUS size S3 contactors with the same mounting rail and terminal arrangement, so the physical swap is straightforward. However, the 3RT1045-3AC20 uses a 24 V 50/60 Hz coil, while the 3RT1044-1FB46 may differ — verify coil voltage and control circuit compatibility before swapping."},{"question":"What compliance documentation does Siemens provide for 3RT1045-3AC20?","answer":"As a SIRIUS product, it carries CE marking for the European market and is designed to meet IEC/EN 60947-4-1. UL and CSA listings are typical for this series; confirm specific certification marks on the nameplate or request the declaration of conformity with your RFQ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-3AC20","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/3RT1045-3AC20 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}}