{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3MR51-0BA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3MR51-0BA0","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3MR51-0BA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3MR51-0BA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS motor starter MCU for AS-Interface, 3RK4320-3MR51-0BA0, direct starter design, 8 A at AC-3 400 V, Trip Class 10, IP55, DC control supply 20.4-26.4 V.","salesMarkdown":"Rated 8 A at AC-3 duty at 400 V, it switches standard three-phase squirrel-cage induction motors up to that current — the AC-3 rating is the load-bearing figure for motor starting, not the resistive AC-1 number. The control supply accepts 20.4 to 26.4 V DC, and the main circuit operating voltage range is 340 to 440 V AC at 50/60 Hz. Three poles serve the main current circuit. IP55 enclosure rating means the unit is dust-protected and withstands water jets — suitable for installation in industrial environments where washdown or airborne particulates are present, but not for submersion or high-pressure washdown zones that would demand IP65 or higher. ## AS-Interface integration and mounting This motor starter communicates via the AS-Interface protocol, with no PROFIBUS DP or PROFINET on board — the bus interface is dedicated to AS-i, so the part fits into an AS-i network segment without a gateway for the motor starter itself. Dimensions are 182 mm wide, 220 mm high, and 145 mm deep. Short-circuit protection is provided by circuit-breakers (not fuses), and the unit is designed for a single motor assignment.","metaTitle":"Siemens 3RK4320-3MR51-0BA0 SIRIUS Motor Starter, 8 A AC-3","metaDescription":"Siemens 3RK4320-3MR51-0BA0 SIRIUS motor starter for AS-Interface. 8 A rated at AC-3 400 V, Trip Class 10, IP55. Current production status.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"145 mm","Width":"182 mm","Height":"220 mm","Trip Class":"CLASS 10","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":"8 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":"8 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":"3 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":"5.5 ... 8 A"}},"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=521262&mlfb=3RK4320-3MR51-0BA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3MR51-0BA0/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy the Siemens 3RK4320-3MR51-0BA0?","answer":"This part is sourced to order against an RFQ through independent distribution. Submit a request for quote to confirm availability and current pricing."},{"question":"Does the 3RK4320-3MR51-0BA0 support PROFINET or PROFIBUS?","answer":"No — this unit supports AS-Interface protocol only. It does not carry PROFIBUS DP or PROFINET interfaces."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3MR51-0BA0","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/3RK4320-3MR51-0BA0 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}}