{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1044-3KB44-0LA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1044-3KB44-0LA0","canonicalUrl":"https://aoctrl.com/siemens/3RT1044-3KB44-0LA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1044-3KB44-0LA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS S3 power contactor, 3RT1044-3KB44-0LA0, 55 A AC-4 at 400 V, 37 kW at 500 V, screw terminals, snap-on DIN rail mounting.","salesMarkdown":"The Siemens 3RT1044-3KB44-0LA0 is a SIRIUS S3-frame power contactor rated for motor switching in the 55 A AC-4 class at 400 V, delivering 37 kW at 500 V and 18.6 kW at 690 V. That AC-4 rating means it's built for reversing, plugging, and inching duty — the hardest start-stop cycles a contactor sees, where the motor is re-energized while still spinning or under load. The coil pulls 24 V DC with a 10 A inrush at that voltage, and the contactor closes in 14–20 ms with an arcing time of 10–15 ms. For lighter motor starting (AC-2), it handles 30 kW at 400 V. The screw-type terminals on the main circuit accept 2x (10–50 mm²) stranded and 2x (0.25–2.5 mm²) solid; auxiliary terminals take 2x (2.5–16 mm²) solid or stranded. ## Duty cycles and endurance Maximum mechanical endurance is 10 million operations. Switching frequency varies by duty: 1 000 cycles/hour for AC-1 and AC-3, 400/h for AC-2, and 300/h for AC-4. The AC-4 limit is the binding constraint for severe applications — at 300 cycles/hour, the contactor is thermally limited by the arc energy during reversal or inching.","metaTitle":"Siemens 3RT1044-3KB44-0LA0 SIRIUS S3 Power Contactor, 55 A A","metaDescription":"Siemens SIRIUS S3 power contactor 3RT1044-3KB44-0LA0, 55 A AC-4 at 400 V, 37 kW at 500 V. Screw terminals, snap-on DIN rail. RoHS compliant. Sourced to order — request quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"191 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"95 mm","at DC":"14 ... 20 ms","Height":"145 mm","Stranded":"2x (10 ... 50 mm²)","Arcing Time":"10 ... 15 ms","Rated Value":"24 V","On The Front":"IP00","Initial Value":"0.7","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":"-40 ... +70 °C","Fastening Method":"screw and snap-on mounting onto 35 mm and 75 mm standard mounting rail","Full-Scale Value":"1.25","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","Design Of The Surge Suppressor":"with varistor","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","closing power of magnet coil at DC":"78 W","holding power of magnet coil at DC":"23 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 (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)","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":"1","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=185585&mlfb=3RT1044-3KB44-0LA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1044-3KB44-0LA0/alternatives.json"},"ai":{"faq":[{"question":"What are the key motor ratings for 3RT1044-3KB44-0LA0?","answer":"AC-4 at 400 V: 55 A. AC-2 at 400 V: 30 kW. Motor power at 500 V: 37 kW. At 690 V: 18.6 kW. The AC-4 rating governs reversing and inching duty."},{"question":"What is the mounting and wiring specification?","answer":"Screw and snap-on mounting onto 35 mm or 75 mm standard DIN rail. Main circuit screw terminals accept 2x (10–50 mm²) stranded; auxiliary terminals accept 2x (2.5–16 mm²) solid or stranded. Side-by-side mounting is permitted."},{"question":"What compliance documentation does this contactor carry?","answer":"RoHS compliant with a substance prohibition date of May 1, 2012. The IP00 rating means it requires a panel enclosure for environmental protection."},{"question":"Where can I buy 3RT1044-3KB44-0LA0 and what is the lead time?","answer":"We source this current-production contactor to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for your quantity and delivery requirements."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1044-3KB44-0LA0","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/3RT1044-3KB44-0LA0 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}}