{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3NR51-0BA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3NR51-0BA0","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3NR51-0BA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3NR51-0BA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS motor starter MCU for AS-Interface, 3RK4320-3NR51-0BA0, direct starter design, CLASS 10 thermal bimetal protection, rated 10 A at AC-3 400 V, IP55 enclosure.","salesMarkdown":"## What this SIRIUS motor starter is It is an electromechanical switching contact device with bimetal motor protection, meaning it combines a contactor and overload relay in one housing for a single motor branch. Operates on a 340 to 440 V AC main circuit and draws control supply from a 20.4 to 26.4 V DC bus. Supports 50/60 Hz line frequencies. ## AS-Interface integration and enclosure This starter communicates natively over AS-Interface (Actuator-Sensor Interface), the bit-level fieldbus common in material handling and assembly lines for wiring sensors and actuators back to a master without a full PROFIBUS or PROFINET backbone. It does not support PROFIBUS DP or PROFINET protocols — the AS-Interface link is the only bus interface. The IP55 enclosure (protection against dust ingress and water jets) suits it for installation in industrial environments where washdown or airborne particulates are a concern — think packaging lines, food processing zones, or machine tool enclosures. ## Protection and ratings The CLASS 10 bimetal overload relay tracks motor current via a thermal model and opens the circuit before winding damage occurs. Short-circuit protection is provided by upstream circuit breakers. Operating frequency is rated at 80 operations per hour maximum — this is not a high-duty-cycle starter for rapid reversing or jogging applications. The unit has three poles for the main current circuit and no integrated brake control outputs. It is a straightforward direct-on-line (DOL) starter — not suitable for star-delta or reversing configurations without external contactors.","metaTitle":"Siemens 3RK4320-3NR51-0BA0 SIRIUS Motor Starter, CLASS 10","metaDescription":"Siemens SIRIUS 3RK4320-3NR51-0BA0 motor starter MCU, direct starter, CLASS 10 trip, 10 A at AC-3 400 V, IP55, AS-Interface. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"145 mm","Width":"182 mm","title":"3RK4320-3NR51-0BA0","Height":"220 mm","Trip Class":"CLASS 10","description":"SIRIUS MCU motor starter Enclosure degree of protection IP55 plastic Communication AS-Interface electromechanically switching Short-circuit protection with circuit breaker DOL starter Brake without Performance class 10.00 A Motor circuit breaker with bi-metal thermal Manual operation without 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":"IP55","PROFIBUS DP protocol":"No","Design Of The Product":"direct starter","Number Of Digital Inputs":"0","Short Circuit Protection":"Yes","at AC at 400 V rated value":"10 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":"10 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 ... +35 °C","Product Component Motor Brake Output":"No","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":"4 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":"7 ... 10 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/aa1366f374580359b626fd86a256a508.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=434985&mlfb=3RK4320-3NR51-0BA0"},"ai":{"faq":[{"question":"Is 3RK4320-3NR51-0BA0 a DOL starter?","answer":"Yes, it is a direct-on-line (DOL) starter. The product design is listed as a direct starter, meaning it connects the motor directly across the line without reduced-voltage starting. It is not suitable for star-delta or reversing configurations without additional external components."},{"question":"What is the enclosure rating of 3RK4320-3NR51-0BA0?","answer":"The protection class is IP55, which provides protection against dust ingress and water jets from any direction. This makes it suitable for installation in washdown environments or areas with airborne particulates."},{"question":"Can 3RK4320-3NR51-0BA0 be used with AS-Interface?","answer":"Yes, this motor starter is specifically designed for AS-Interface communication. The protocol is supported natively, and the product designation is 'motor starter MCU for AS-Interface'. It does not support PROFIBUS DP or PROFINET protocols."},{"question":"Where can I buy 3RK4320-3NR51-0BA0 at a good price?","answer":"This part is sourced to order. Availability and pricing are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3NR51-0BA0","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/3RK4320-3NR51-0BA0 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}}