{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3LQ54-0BA2","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3LQ54-0BA2","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3LQ54-0BA2","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3LQ54-0BA2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS MCU motor starter for AS-Interface, direct starter, 6.3 A AC-3 at 400 V, Class 10, IP54, 2 digital inputs, brake output, 205 x 245 x 215 mm.","salesMarkdown":"The Siemens 3RK4320-3LQ54-0BA2 is a SIRIUS MCU (Motor Control Unit) — a compact, AS-Interface-bus-ready direct starter that integrates a contactor, overload relay, and communication interface in one housing. It's sized for motor loads up to 6.3 A in AC-3 duty at 400 V, with a bimetal overload trip characteristic in Class 10, so it protects standard induction motors during start-up without nuisance tripping on normal acceleration. This unit communicates over AS-Interface (the only bus protocol on board; no PROFINET or PROFIBUS DP), giving you two digital inputs for feedback from the line — limit switches, position sensors, or E-stop status — wired back to the AS-i master without a separate I/O block. The control supply is 20.4–26.4 VDC, and the main power circuit takes 340–440 VAC at 50/60 Hz. It includes a motor brake output component slot; short-circuit protection coordinates with upstream circuit-breakers. The enclosure measures 205 mm deep, 245 mm wide, and 215 mm high, with an IP54 rating — sealed against dust ingress and splashing water, so it's suited for installation in industrial environments where washdown isn't routine but airborne particulates are present. Operating ambient temperature spans -25 to +50 °C, with a maximum switching frequency of 80 operations per hour. The device is a three-pole direct starter (no reversing contactor inside), so for a reversing or two-speed application you'd pair two of these units and handle the interlocking in the AS-i master logic.","metaTitle":"Siemens 3RK4320-3LQ54-0BA2 SIRIUS MCU Motor Starter","metaDescription":"Siemens SIRIUS 3RK4320-3LQ54-0BA2 MCU motor starter, 6.3 A at AC-3/400V, AS-Interface, Class 10, IP54. Current production. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"205 mm","Width":"245 mm","title":"3RK4320-3LQ54-0BA2","Height":"215 mm","Trip Class":"CLASS 10","description":"SIRIUS MCU motor starter Enclosure degree of protection IP54 metal Communication AS-Interface electromechanically switching Short-circuit protection with circuit breaker DOL starter Brake 230 V AC (internal) Performance class 6.30 A Motor circuit breaker with bi-metal thermal Rotary operating mechanism gray/black Connection power M screw connection Standard product","Type Of Voltage":"DC","lifecycle_stage":"current","Bus Communication":"Yes","Mounting Position":"+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface","PROFINET protocol":"No","Product Brand Name":"SIRIUS","Type Of Assignment":"1","Product Designation":"motor starter MCU for AS-Interface","protection class IP":"IP54","PROFIBUS DP protocol":"No","Design Of The Product":"direct starter","Number Of Digital Inputs":"2","Short Circuit Protection":"Yes","at AC at 400 V rated value":"6.3 A","brake control with 24 V DC":"No","Operating Frequency Minimum":"80 1/h","brake control with 180 V DC":"No","brake control with 400 V AC":"No","brake control with 500 V DC":"No","Type Of The Motor Protection":"bimetal","at AC-3 at 400 V rated value":"6.3 A","Operating Voltage Rated Value":"340 ... 440 V","Substance Prohibitance (Date)":"05/01/2012","Design Of The Switching Contact":"electromechanical","Operating Frequency 1 Rated Value":"50 Hz","Operating Frequency 2 Rated Value":"60 Hz","Design Of Short-Circuit Protection":"circuit-breakers","Ambient Temperature During Operation":"-25 ... +50 °C","Product Component Motor Brake Output":"Yes","Type Of Voltage Of The Supply Voltage":"DC","reference code according to IEC 81346-2":"Q","Number Of Poles For Main Current Circuit":"3","control supply voltage at DC rated value":"20.4 ... 26.4 V","with low demand rate according to SN 31920":"50 %","protocol is supported AS-Interface protocol":"Yes","with high demand rate according to SN 31920":"75 %","operating power at AC-3 at 400 V rated value":"2.2 kW","Product Extension Braking Module For Brake Control":"No","Relative Negative Tolerance Of The Operating Frequency":"-10 %","Relative Positive Tolerance Of The Operating Frequency":"10 %","Type Of Electrical Connection For Main Current Circuit":"screw-type terminals","maximum short-circuit current breaking capacity (Icu) at 400 V rated value":"50 000 A","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"4.5 ... 6.3 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/85daba235257fc048423123ee786b0b6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=271026&mlfb=3RK4320-3LQ54-0BA2"},"ai":{"faq":[{"question":"Where can I buy the 3RK4320-3LQ54-0BA2?","answer":"This part is sourced to order against an RFQ through independent distribution channels. Contact our sourcing desk for a current price and availability quote — stock and lead time are confirmed at quote time, not on this listing."},{"question":"What is the difference between MCU and MSC motor starter?","answer":"An MCU (Motor Control Unit) like this one is a compact, bus-communicating direct starter with integrated overload and communication. An MSC (Motor Starter Combination) typically includes a disconnect switch, short-circuit protection, and overload in one package, often with a higher SCCR. The MCU is designed for distributed, AS-Interface-controlled architectures where space is tight."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3LQ54-0BA2","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/3RK4320-3LQ54-0BA2 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T19:47:38.189Z","lastPublished":"2026-07-22T19:47:38.189Z","indexable":true}}