{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1AL20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1AL20","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1AL20","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AL20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, size S3, 3RT1045-1AL20, 45 kW at 500 V, screw-type terminals, 70 x 146 x 139 mm.","salesMarkdown":"## SIRIUS S3 power contactor – panel-fit and wiring The Siemens SIRIUS 3RT1045-1AL20 is a size S3 power contactor rated for motor loads up to 45 kW at 500 V and 21.1 kW at 690 V. It snaps onto 35 mm or 75 mm DIN rail and measures 70 mm wide by 146 mm tall by 139 mm deep — a standard S3 footprint that fits most motor control centre buckets and enclosure backplates without crowding adjacent devices. Main power wiring accepts solid or stranded conductors up to 50 mm² (stranded) or 4 mm² per solid pair, with screw-type terminals that are field-friendly for panel builders. The auxiliary circuit handles 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V — enough for most PLC or relay interface loads. ## Switching performance and lifecycle Electrical switching frequency varies by duty: 1 000 cycles/hour under AC-3 (motor starting), 900 under AC-1 (resistive), 400 under AC-2 (slip-ring motor), and 300 under AC-4 (plugging / inching). Arcing time sits between 10 and 25 ms depending on the load — standard for a contactor this size. The contactor is rated for both 50 Hz and 60 Hz supplies, with an operating range of 0.8 to 1.1 times rated voltage at 50 Hz and 0.85 to 1.1 at 60 Hz. Side-by-side mounting is allowed, so multiple units can be ganged without derating — useful for compact motor starter assemblies. This part carries a current-production lifecycle status. No official successor has been announced — the 3RT1045-1AL20 remains the active S3 screw-terminal variant in the SIRIUS family.","metaTitle":"Siemens 3RT1045-1AL20 SIRIUS Power Contactor, S3, 45 kW at 5","metaDescription":"Siemens SIRIUS 3RT1045-1AL20 power contactor, size S3, rated 45 kW at 500 V. Screw terminals, 70 mm wide, 139 mm deep. Active production. Order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"139 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 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":"230 V","at 500 V rated value":"45 kW","at 60 Hz rated value":"230 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":"screw-type 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 (20 ... 16), 2x (18 ... 14), 1x 12","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 (0.5 ... 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)","Thermal Short-Time Current Limited To 10 S":"760 A","Finely Stranded Without Core End Processing":"2x (10 ... 35 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=285993&mlfb=3RT1045-1AL20","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AL20/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RT1045-1AL20 and how do I get a price?","answer":"It is sourced to order against an RFQ through independent distribution. Submit a quote request; availability and pricing are confirmed at that time."},{"question":"What is 3RT1045-1AL20's depth?","answer":"The depth is 139 mm."},{"question":"What solid conductor sizes does 3RT1045-1AL20 accept?","answer":"The main terminals accept solid conductors in pairs: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and up to 2x (0.75 to 4 mm²)."},{"question":"Will 3RT1045-1AL20 drop into a panel specified around 3RT1044-1FB46 without rewiring?","answer":"Both are SIRIUS S3 frame contactors with the same mounting footprint and screw terminals, so the mechanical fit is identical. However, the 3RT1044-1FB46 is a different electrical rating — verify your load current and coil voltage before swapping."},{"question":"What compliance documentation does Siemens provide for 3RT1045-1AL20?","answer":"Siemens SIRIUS contactors typically carry CE, UL, CSA, and CCC certifications; RoHS and REACH declarations are available from the manufacturer. Specific document numbers are not listed here — request them with your RFQ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1AL20","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/3RT1045-1AL20 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}}