{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3MR51-1BA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3MR51-1BA0","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3MR51-1BA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3MR51-1BA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RK4320-3MR51-1BA0 reversing motor starter, AS-Interface bus, 8 A AC-3 at 400 V, Class 10 bimetal overload protection, IP55, 24 V DC control, 145 x 182 x 220 mm.","salesMarkdown":"## Active production — what that means for the BOM line The 3RK4320-3MR51-1BA0: No stock-holding claim — confirmed per quote. ## Reversing starter for AS-Interface — the bus integration angle This is a reversing starter designed for AS-Interface bus communication, not PROFIBUS or PROFINET. It integrates into an AS-i network as a single addressable node, handling forward/reverse motor control with built-in bimetal overload protection and short-circuit protection via circuit-breakers. Control supply is 20.4-26.4 V DC — standard 24 V DC panel rail, but note the tight tolerance band; a rail that dips below 20.4 V will drop the starter. ## 8 A AC-3 — the motor-switching current that matters The same 8 A figure appears for AC at 400 V, confirming the thermal current matches the switching rating. Operating frequency is capped at 80 operations per hour — this is not a high-duty-cycle starter for rapid reversing. For applications needing frequent starts, check the thermal accumulation in the bimetal element. ## Mounting and panel fit — 145 x 182 x 220 mm Dimensions are 145 mm depth, 182 mm width, 220 mm height. IP55 protection means it is dust-protected and can handle hose-down from any direction — suitable for light washdown environments like food processing or packaging lines, but not submersion.","metaTitle":"Siemens 3RK4320-3MR51-1BA0 reversing starter, AS-Interface","metaDescription":"Siemens SIRIUS reversing motor starter, 8 A at AC-3 400 V, Class 10 bimetal overload, IP55, AS-Interface bus. Active production — quoted to order. Request RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"145 mm","Width":"182 mm","title":"3RK4320-3MR51-1BA0","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 Reversing starter Brake without Performance class 8.00 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":"reversing 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,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/39b2c2431866065d91587ed678d87824.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=15755&mlfb=3RK4320-3MR51-1BA0"},"ai":{"faq":[{"question":"What is the AC-3 rating and what does it mean for motor sizing?","answer":"This is the motor switching current, not the thermal continuous current. For a three-phase 400 V motor, 8 A corresponds roughly to a 3-4 kW output at full load. The Class 10 bimetal overload provides motor protection against locked-rotor conditions."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3MR51-1BA0","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/3RK4320-3MR51-1BA0 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}}