{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1044-1BW40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1044-1BW40","canonicalUrl":"https://aoctrl.com/siemens/3RT1044-1BW40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1044-1BW40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, size S3, 3RT1044-1BW40, 37 kW at 500 V AC-3, screw-type terminals, snap-on mounting.","salesMarkdown":"Rated for 37 kW at 500 V in AC-3 duty (motor starting/switching) and 55 A at 400 V in AC-4 duty (reversing/inching), the contactor handles the mechanical endurance of 10 million typical cycles. The AC-3 switching rate reaches 1000 operations per hour; AC-4 is derated to 300 operations per hour. Main circuit connections use screw-type terminals. Solid wire acceptance ranges from 2x 0.5...1.5 mm² up to 2x 0.75...4 mm²; stranded wire accepts 2x 10...50 mm². The auxiliary/control circuit accepts 2x 2.5...16 mm² solid or stranded. The enclosure carries IP20 on the front with the cover or box terminal fitted; the terminal itself is rated IP00. Dimensions are 146 mm high, 70 mm wide, 152 mm deep. The 70 mm width is a standard S3 footprint, allowing direct replacement in panels where a size S3 contactor was originally specified. Snap-on mounting onto 35 mm or 75 mm DIN rail speeds installation; screw mounting is also supported for vibration-prone environments. Side-by-side mounting is explicitly permitted, so multiple contactors can be ganged without additional spacing — useful for grouped motor starter assemblies where panel width is constrained. The contactor carries no known material compliance gaps for EU or global industrial markets. ## Ratings in Context The 37 kW rating at 500 V AC-3 is the headline motor-switching capacity. At 690 V, the motor power rating is 18.6 kW, reflecting the reduced current capability at higher voltage. For resistive loads (AC-1), the switching rate is 1000 operations per hour; for AC-4 reversing duty, the rate drops to 300 operations per hour due to increased contact wear. The DC switching ratings are modest: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V. Arcing time in DC circuits is 14...20 ms, compared to 10...15 ms for AC. This contactor is primarily intended for AC motor loads; DC applications should be verified against the load break current. The wider storage range reflects handling and transport conditions, not running operation.","metaTitle":"Siemens 3RT1044-1BW40 SIRIUS Power Contactor, Size S3, 37 kW","metaDescription":"Siemens 3RT1044-1BW40 SIRIUS power contactor, size S3. 37 kW at 500 V AC-3, 55 A at 400 V AC-4. Screw terminals, snap-on 35/75 mm rail. IP20 front. Current production. Sourced to o","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"152 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":"48 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":"1 000 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":"37 kW","at 690 V rated value":"18.6 kW","Side-By-Side Mounting":"Yes","at 1000 V rated value":"30 W","For Main Current Circuit":"screw-type terminals","at AC-2 at 400 V rated value":"30 kW","at AC-4 at 400 V rated value":"55 A","Substance Prohibitance (Date)":"05/01/2012","at 40 °C minimum permissible":"35 mm²","at 60 °C minimum permissible":"35 mm²","Insulation Voltage Rated Value":"1 000 V","at 230 V at 60 °C rated value":"34 kW","at 690 V at 60 °C rated value":"102 kW","at 1000 V at 60 °C rated value":"66 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: 125 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":"600 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":"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=375681&mlfb=3RT1044-1BW40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1044-1BW40/alternatives.json"},"ai":{"faq":[{"question":"What is the closest alternative to 3RT1044-1BW40?","answer":"The 3RT1044-1FB46 is a functional peer within the same SIRIUS size S3 family. The key difference is the coil voltage: the 1BW40 uses a 48 V DC coil (rated value 48 V), while the 1FB46 uses a different coil voltage. Verify coil compatibility before substituting."},{"question":"Will 3RT1044-1BW40 drop into a panel specified for 3RT1044-1FB46?","answer":"Mechanically yes — both are size S3 with the same 70 mm width, 146 mm height, 152 mm depth, and snap-on DIN rail mounting. The wiring terminals are identical. The only difference is coil voltage, so verify the control circuit voltage before substitution."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1044-1BW40","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/3RT1044-1BW40 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}}