{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1044-3EB05","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1044-3EB05","canonicalUrl":"https://aoctrl.com/siemens/3RT1044-3EB05","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1044-3EB05","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS, Size S3 power contactor, 3RT1044-3EB05, screw-type terminals, 55 A AC-4 at 400 V, 37 kW at 500 V, IP20 front, IP00 terminal.","salesMarkdown":"## SIRIUS Size S3 power contactor — 55 A AC-4 at 400 V The Siemens 3RT1044-3EB05 is a SIRIUS Size S3 power contactor rated for motor switching at 55 A in AC-4 duty at 400 V, and delivers 37 kW at 500 V or 18.6 kW at 690 V. The coil is 24 V at 50 Hz with a holding power of 30 W. Side-by-side mounting is permitted, which simplifies multi-contactor panels. Dimensions are 163 mm height, 80 mm width, 139 mm depth — the depth (139 mm) is a key fit check for shallow enclosures. Main circuit terminals are screw-type, accepting solid conductors 2x (0.25 to 2.5 mm²) or stranded 2x (10 to 50 mm²). ## Duty ratings and thermal limits Rated for AC-2 at 400 V at 30 kW and AC-4 at 400 V at 55 A — the AC-4 figure governs plugging and inching duty where the contactor makes and breaks stalled-rotor current. Maximum switching rates: 1 000 cycles/hour for AC-1 and AC-3, 400 for AC-2, 300 for AC-4. Pollution degree 3 (industrial environment). DC switching ratings are specified per voltage: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, 3 A at 400 V. Arcing time is 10 to 15 ms; shock withstand is 10.6 g for 5 ms (AC) and 6.2 g for 10 ms (AC).","metaTitle":"Siemens 3RT1044-3EB05 SIRIUS Power Contactor, 55 A AC-4 at 4","metaDescription":"Siemens SIRIUS 3RT1044-3EB05 power contactor, Size S3, 55 A AC-4 at 400 V, 37 kW at 500 V. Screw terminals, IP20 front. Current production. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"139 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"80 mm","at AC":"10.6g / 5 ms, 6.2g / 10 ms","at DC":"14 ... 20 ms","Height":"163 mm","Stranded":"2x (10 ... 50 mm²)","at 50 Hz":"0.8 ... 1.1","Arcing Time":"10 ... 15 ms","On The Front":"IP20; IP20 on the front with cover / box terminal","1 Rated Value":"50 Hz","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","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":"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","Design Of The Surge Suppressor":"with RC elements","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":"spring-loaded terminals","With Type Of Assignment 2 Required":"fuse gL/gG: 125 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":"600 A","Finely Stranded Without Core End Processing":"2x (0.25 ... 2.5 mm²)","apparent holding power of magnet coil at AC":"21 VA","apparent pick-up power of magnet coil at AC":"218 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":"0.61","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Inductive Power Factor With The Holding Power Of The Coil":"0.26","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":"1","number of NO contacts for auxiliary contacts instantaneous contact":"1","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=254758&mlfb=3RT1044-3EB05","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1044-3EB05/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings for 3RT1044-3EB05?","answer":"AC-4 at 400 V: 55 A; AC-2 at 400 V: 30 kW; 500 V: 37 kW; 690 V: 18.6 kW. Coil is 24 V at 50 Hz, 30 W holding. Mechanical life 10 million operations."},{"question":"Where can I buy 3RT1044-3EB05?","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":"What is the depth of 3RT1044-3EB05?","answer":"Depth is 139 mm. Overall dimensions: 163 mm height, 80 mm width."},{"question":"What wire sizes does the 3RT1044-3EB05 accept?","answer":"Solid conductors: 2x (0.25 to 2.5 mm²). Stranded: 2x (10 to 50 mm²). Also accepts 2x (2.5 to 16 mm²) solid or stranded. Terminals are screw-type."},{"question":"Does 3RT1044-3EB05 drop into a panel designed for 3RT1044-1FB46?","answer":"Both are Size S3 SIRIUS contactors sharing the same mounting rail (35 mm or 75 mm) and side-by-side capability. The terminal type differs — this unit uses screw terminals; verify the peer's terminal style before assuming direct swap without rewiring."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1044-3EB05","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/3RT1044-3EB05 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}}