{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3PQ51-0BA2","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3PQ51-0BA2","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3PQ51-0BA2","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3PQ51-0BA2","rawCanonicalId":null},"summary":{"shortDescription":"SIRIUS 3RK4320-3PQ51-0BA2, motor starter MCU for AS-Interface, direct starter, 12 A AC-3 at 400 V, IP54, DC control supply 20.4-26.4 V, built-in brake output.","salesMarkdown":"## What is the 3RK4320-3PQ51-0BA2? The SIRIUS 3RK4320-3PQ51-0BA2 is a motor starter MCU (Motor Control Unit) designed for AS-Interface networks — a direct starter with electromechanical switching contacts and bimetal motor protection. Built for washdown or dusty environments with an IP54 enclosure, this starter handles ambient temperatures from -25 to +50 °C. The DC control supply runs on 20.4 to 26.4 V, and the unit includes a built-in motor brake output — a feature that saves an external contactor on applications needing mechanical holding. ## AS-Interface Integration and Dimensions This starter communicates natively over AS-Interface (the protocol is supported), with two digital inputs on board. It does not support PROFINET or PROFIBUS DP, so if your line runs those fieldbuses, you'll need a gateway or a different variant. Physical footprint: 245 mm wide, 215 mm high, 205 mm deep.","metaTitle":"SIRIUS 3RK4320-3PQ51-0BA2 Motor Starter, 12 A AC-3","metaDescription":"SIRIUS 3RK4320-3PQ51-0BA2 motor starter MCU for AS-Interface. 12 A AC-3 at 400 V, IP54, DC control, built-in brake output. Current production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"205 mm","Width":"245 mm","title":"3RK4320-3PQ51-0BA2","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 12.00 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":"12 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":"12 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":"5.5 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","breaking capacity maximum short-circuit current (Icu) at 400 V rated value":"50 000 A","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"9 ... 12.5 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/f987c6a016a41f06a48e819bc3c1385a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=323316&mlfb=3RK4320-3PQ51-0BA2"},"ai":{"faq":[{"question":"Where can I purchase the SIRIUS 3RK4320-3PQ51-0BA2 motor starter?","answer":"The 3RK4320-3PQ51-0BA2 is sourced to order against an RFQ through independent industrial-automation distribution. Submit a request for quote (RFQ) to confirm current availability and pricing at the time of your order."},{"question":"Does the 3RK4320-3PQ51-0BA2 include a built-in brake?","answer":"Yes, the product component includes a motor brake output. This saves adding a separate brake contactor for applications like vertical loads or holding brakes."},{"question":"Is the 3RK4320-3PQ51-0BA2 compatible with AS-Interface?","answer":"Yes, the AS-Interface protocol is supported. The unit communicates natively on AS-Interface networks and does not require a gateway for that protocol."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3PQ51-0BA2","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/3RK4320-3PQ51-0BA2 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}}