{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1AK20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1AK20","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1AK20","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AK20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT1045-1AK20 power contactor, S3 frame, screw-type terminals, 45 kW at 500 V AC-3, 21.1 kW at 690 V, IP20 front.","salesMarkdown":"## Integrator's Quick Assessment The Siemens 3RT1045-1AK20 is a SIRIUS S3-frame power contactor rated for motor switching at 45 kW on a 500 V AC-3 supply and 21.1 kW at 690 V AC-3. Front protection is IP20 with the cover or box terminal installed; the terminal body itself is IP00, meaning the wiring compartment must be inside a rated enclosure. Operating ambient spans -25 to +60 °C, with storage from -55 to +80 °C — adequate for most indoor industrial panels but verify if the panel ambient exceeds 60 °C near ovens or furnaces. ## Motor Duty and Switching Performance This contactor is sized for AC-3 motor starting and AC-4 inching/plugging duty. At AC-3 it manages up to 1 000 switching cycles per hour; at AC-4 the rate drops to 300 cycles per hour due to the higher electrical stress of breaking locked-rotor current. The mechanical life is typical at 10 000 000 operations, so the limiting factor in high-duty-cycle applications will be electrical wear on the contacts, not the mechanism. Coil operating range spans 0.8 to 1.1 times rated voltage at 50 Hz and 0.85 to 1.1 at 60 Hz, with an arcing time of 10 to 15 ms and total opening time of 10 to 25 ms at AC. For a 24 VDC control circuit, the auxiliary contact ratings are 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — sufficient for pilot duty on most PLC outputs but check the inrush of the connected load. ## Wiring and Panel Integration Main power terminals accept solid conductors: 2x (0.5... 1.5 mm²), 2x (0.75... 2.5 mm²), or max 2x (0.75... 4 mm²). Stranded connections use 2x (10... 50 mm²) for the main circuit. The auxiliary and coil terminals accept 2x (2.5... 16 mm²) solid or stranded.","metaTitle":"Siemens 3RT1045-1AK20 SIRIUS Power Contactor, 45 kW at 500 V","metaDescription":"Siemens SIRIUS 3RT1045-1AK20 power contactor, S3 size, 45 kW at 500 V AC-3, 21.1 kW at 690 V. Screw terminals, IP20 front. Active production, factory-fresh and fully warrantied.","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":"120 V","at 500 V rated value":"45 kW","at 60 Hz rated value":"120 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=247036&mlfb=3RT1045-1AK20","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AK20/alternatives.json"},"ai":{"faq":[{"question":"What are the key motor ratings for this contactor?","answer":"At 500 V AC-3 duty it is rated for 45 kW motor load; at 690 V AC-3 it is rated for 21.1 kW. The mechanical life is 10 000 000 operations typical, and the maximum switching rate at AC-3 is 1 000 cycles per hour."},{"question":"What is the mounting method and panel space required?","answer":"It mounts via screw and snap-on onto 35 mm or 75 mm standard DIN rail. Dimensions are 146 mm height, 70 mm width, and 139 mm depth. Side-by-side mounting is permitted without derating."},{"question":"What wire sizes does the main circuit accept?","answer":"The screw-type main terminals accept stranded conductors of 2x (10... 50 mm²). For solid conductors, the terminals accept 2x (0.5... 1.5 mm²), 2x (0.75... 2.5 mm²), or max 2x (0.75... 4 mm²)."},{"question":"What is the closest functional second-source to this contactor?","answer":"The 3RT1034-1AN60-1AA0 is a functional peer within the SIRIUS S3 frame family. However, verify coil voltage, auxiliary contact configuration, and terminal ratings against your specific panel wiring before substitution — the frame size and mounting are shared, but electrical ratings differ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1AK20","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/3RT1045-1AK20 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}}