{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1QB44-3MA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1QB44-3MA0","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1QB44-3MA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1QB44-3MA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, size S3, order code 3RT1045-1QB44-3MA0, 66 A AC-4 at 400 V, screw terminals, 70 mm width, 146 mm height, 201 mm depth.","salesMarkdown":"The 70 mm width and 146 mm height fit the S3 footprint; depth is 201 mm, so account for that behind the gland plate when laying out the enclosure. Side-by-side mounting is allowed, meaning you can gang contactors without a gap, but the thermal derating curve in the datasheet governs the actual current when packed tight. ## Termination and wiring Main current circuit uses screw-type terminals. Stranded: two conductors from 10 mm² to 50 mm² — that's the heavy power feed. Control circuit wiring accepts solid or stranded from 0.5 mm² to 16 mm². The terminal itself is rated IP00 (unprotected), but the front of the contactor with cover or box terminal carries IP20, so finger-safe once the enclosure door is shut. ## Environmental and operating limits The coil holds at 24 V nominal with a 0.8 to 1.1 times rated voltage operating range.","metaTitle":"Siemens 3RT1045-1QB44-3MA0 SIRIUS Power Contactor, S3, 66 A","metaDescription":"Siemens SIRIUS 3RT1045-1QB44-3MA0 power contactor, size S3, 66 A AC-4 at 400 V, 37 kW AC-2. Screw terminals, DIN rail mount. Active production. RoHS compliant.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"201 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)","Width":"70 mm","at DC":"14 ... 20 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","Arcing Time":"10 ... 15 ms","Rated Value":"24 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","Design Of The Surge Suppressor":"with diode assemblies","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","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 (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)","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":"2","number of NO contacts for auxiliary contacts instantaneous contact":"2","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=351997&mlfb=3RT1045-1QB44-3MA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1QB44-3MA0/alternatives.json"},"ai":{"faq":[{"question":"What are the key switching ratings for this contactor?","answer":"AC-4 at 400 V: 66 A, which is the severe-duty motor reversing rating. AC-2 at 400 V: 37 kW. AC-3 maximum switching frequency is 1 000 operations per hour; AC-4 maximum is 300 operations per hour."},{"question":"What compliance documentation is available?","answer":"RoHS compliance is confirmed with a substance prohibition date of May 1, 2012. No UL or CSA listing is stated in the spec record."},{"question":"What is the physical size of this contactor?","answer":"Width 70 mm, height 146 mm, depth 201 mm. It is size S3 and mounts on 35 mm or 75 mm standard mounting rail."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1QB44-3MA0","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/3RT1045-1QB44-3MA0 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}}