{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA1145-4FB44-1BP4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA1145-4FB44-1BP4","canonicalUrl":"https://aoctrl.com/siemens/3RA1145-4FB44-1BP4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA1145-4FB44-1BP4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS non-fused motor starter, direct starter, Size S3, 40 A at 480/600 V, Class 10 thermal bimetallic overload, snap-on 35 mm rail, 220 x 70 x 330 mm.","salesMarkdown":"The Siemens 3RA1145-4FB44-1BP4 is a SIRIUS non-fused motor starter — a direct-starter assembly that combines a contactor and a thermal bimetallic overload relay in one S3-size package, rated for AC-3 switching up to 690 V. The thermal bimetallic design provides a true RMS current sensing that handles the starting inrush without nuisance trips, unlike electronic overloads that can be more sensitive to harmonics. Snap-on mounting on a 35 mm standard rail in a vertical position keeps panel integration straightforward — no screws or brackets needed for the rail itself. The S3 size is a common footprint in Siemens SIRIUS load feeders, meaning it slots into existing S3 busbar systems and link modules without adapters. Rated 40 A at both 480 V and 600 V, this starter handles motor loads up to 40 hp at 575/600 V and 30 hp at 460/480 V. At 400 V it delivers 18,500 W. These are the AC-3 motor-switching ratings — the values that govern real-world motor starting, not the resistive AC-1 numbers. The 690 V maximum gives headroom for 600 V class systems without derating. The supplied contactor is a 3RT1044-1BP40 and the link module is 3RA1941-1BA00 — both standard SIRIUS S3 components. If you already have an S3 busbar system, this starter mates directly; no special adapter needed. The main terminal accepts stranded wire from 2.5 to 70 mm², or 2x (10 to 50 mm²), which covers most motor feeds up to 40 A without needing a separate terminal block. The enclosure measures 220 mm deep, 70 mm wide, and 330 mm high. Clearance requirements: 90 mm upward, 10 mm forward, 10 mm downward, 12 mm at the side, and 0 mm backward (–,).","metaTitle":"Siemens 3RA1145-4FB44-1BP4 SIRIUS Non-Fused Motor Starter","metaDescription":"Siemens 3RA1145-4FB44-1BP4 SIRIUS non-fused motor starter, 40 A at 480/600 V, Class 10, thermal overload, snap-on 35 mm rail. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"220 mm","Width":"70 mm","Height":"330 mm","Upwards":"90 mm","Forwards":"10 mm","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"12 mm","Rated Value":"230 V","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-55 ... +80 °C","Fastening Method":"snap-on fastening on 35 mm standard rail","Mounting Position":"vertical","Product Brand Name":"SIRIUS","Type Of Assignment":"1","Degree Of Pollution":"3","Product Designation":"non-fused motor starter","Size Of Load Feeder":"S3","at 230 V rated value":"7.5 hp","at 400 V rated value":"18 500 W","at 480 V rated value":"40 A","at 600 V rated value":"40 A","Design Of The Product":"direct starter","at 110/120 V rated value":"3 hp","at 200/208 V rated value":"15 hp","at 220/230 V rated value":"15 hp","at 460/480 V rated value":"30 hp","at 575/600 V rated value":"40 hp","Of The Supplied Contactor":"3RT1044-1BP40","For Main Contacts Stranded":"2.5 ... 70 mm², 2x (10 ... 50 mm²)","Of The Supplied Link Module":"3RA1941-1BA00","Size Of The Circuit-Breaker":"S3","at AC-3 rated value maximum":"690 V","Substance Prohibitance (Date)":"03/01/2017","Design Of The Overload Release":"thermal (bimetallic)","Design Of The Switching Contact":"electromechanical","Operating Frequency Rated Value":"50 ... 60 Hz","at AWG cables for main contacts":"1x (10 ... 2/0), 2x (10 ... 1/0)","Design Of The Short-Circuit Trip":"magnetic","Of The Supplied Circuit-Breakers":"3RV1041-4FA15","Product Extension Auxiliary Switch":"Yes","holding power of magnet coil at DC":"15 W","Surge Voltage Resistance Rated Value":"6 kV","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","shock resistance according to IEC 60068-2-27":"6g / 11 ms","Of The Supplied Standard Mounting Rail Adapter":"3RA1942-1AA00","at 400 V according to IEC 60947-4-1 rated value":"50 000 A","operational current at AC-3 at 400 V rated value":"35 A","Type Of Electrical Connection For Main Current Circuit":"screw-type terminals","Mechanical Service Life (Switching Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"520 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"28 ... 40 A","Connectable Conductor Cross-Section For Main Contacts Finely Stranded With Core End Processing":"2.5 ... 50 mm²"}},"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=50538&mlfb=3RA1145-4FB44-1BP4","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA1145-4FB44-1BP4/alternatives.json"},"ai":{"faq":[{"question":"What is the trip class for Siemens 3RA1145-4FB44-1BP4?","answer":"The trip class is Class 10, meaning the overload relay will trip within 10 seconds under locked-rotor conditions — suitable for standard motor protection on pumps, fans, and conveyors."},{"question":"Can Siemens 3RA1145-4FB44-1BP4 replace 3RA1145-4FB44-1BP3?","answer":"The evidence does not list a direct successor relationship, but both are SIRIUS S3 non-fused motor starters. Verify the supplied contactor and link module match your existing assembly — the 3RA1145-4FB44-1BP4 ships with contactor 3RT1044-1BP40 and link module 3RA1941-1BA00."},{"question":"Where can I buy Siemens 3RA1145-4FB44-1BP4?","answer":"This part is sourced to order. Contact our sales team for current pricing and lead time at quote."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA1145-4FB44-1BP4","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/3RA1145-4FB44-1BP4 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}}