{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1044-1AL20-ZW95","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1044-1AL20-ZW95","canonicalUrl":"https://aoctrl.com/siemens/3RT1044-1AL20-ZW95","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1044-1AL20-ZW95","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, order code 3RT1044-1AL20-ZW95, size S3, 37 kW at 500 V AC-3, screw terminals, snap-on DIN rail.","salesMarkdown":"It carries a rated power of 37 kW at 500 V AC-3 duty, and 18.6 kW at 690 V — the AC-3 rating is the one that governs motor switching, not the AC-1 resistive figure. That means for a 37 kW, 500 V motor on a conveyor or pump, this contactor handles the inrush and breaking without welding contacts. Mounts via screw or snap-on onto 35 mm and 75 mm standard DIN rails — the snap-on feature speeds panel assembly, and the 70 mm width plus 146 mm height fits the S3 footprint common in Siemens SIRIUS motor starter combinations. Solid wire accepts 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and up to 2x (0.75 to 4 mm²). Stranded wire takes 2x (10 to 50 mm²) for the larger power feeds. That range covers most motor branch circuits from fractional kW up to the 37 kW rating — the 50 mm² stranded capacity is enough for the full load current without needing a terminal adapter. ## Environmental and protection IP20 on the front with cover or box terminal; the terminal itself is IP00, so it expects enclosure protection in the panel.","metaTitle":"Siemens 3RT1044-1AL20-ZW95 SIRIUS Power Contactor, S3, 37 kW","metaDescription":"Siemens 3RT1044-1AL20-ZW95 SIRIUS power contactor, size S3, rated 37 kW at 500 V AC-3. Screw terminals, snap-on DIN rail. 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 (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)","Width":"70 mm","at AC":"10 ... 19 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":"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":"230 V","at 500 V rated value":"37 kW","at 60 Hz rated value":"230 V","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","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)","apparent holding power of magnet coil at AC":"25 VA","apparent pick-up power of magnet coil at AC":"247 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":"0.62","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Inductive Power Factor With The Holding Power Of The Coil":"0.27","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=64787&mlfb=3RT1044-1AL20-ZW95","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1044-1AL20-ZW95/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional second-source — 3RT1036-1AB00?","answer":"The 3RT1036-1AB00 is a smaller SIRIUS contactor (size S0) and will not drop into a panel wired for the S3 frame without rewiring the power terminals and possibly the mounting rail. The 3RT1044-1AL20-ZW95 is the correct S3 size for 37 kW at 500 V; the 3RT1036 is rated lower and has a different terminal layout."},{"question":"What is the depth of the 3RT1044-1AL20-ZW95?","answer":"The depth is 139 mm. That is the dimension from the mounting surface to the front of the contactor, including the terminals."},{"question":"What solid wire sizes does the 3RT1044-1AL20-ZW95 accept?","answer":"The screw terminals accept solid wire in these combinations: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and up to 2x (0.75 to 4 mm²)."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1044-1AL20-ZW95","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/3RT1044-1AL20-ZW95 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}}