{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3AQ51-0BA3","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3AQ51-0BA3","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3AQ51-0BA3","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3AQ51-0BA3","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS motor starter MCU for AS-Interface, 3RK4320-3AQ51-0BA3, direct starter design, 0.63 A rated current at AC-3 400 V, Trip Class 10, IP54.","salesMarkdown":"## AS-Interface motor starter with integrated brake control Its 0.63 A AC-3 rating at 400 V means it switches a motor load up to that current under the heaviest starting duty (inductive break), and the Trip Class 10 bimetal overload protects standard squirrel-cage motors during startup without nuisance tripping on normal acceleration. This is a current-production part — not a last-time-buy or obsolete line — so it remains a straightforward BOM line for new panel builds or AS-i drop replacements. The AS-Interface protocol support means it plugs directly into an AS-i network without a separate gateway module for the motor starter function, saving a slot in the cabinet. The 0.63 A at AC-3 400 V is the motor-rated current — not the thermal or resistive rating. For a 400 V three-phase induction motor, this covers a roughly 0.25 kW load (about 0.33 hp). If your motor nameplate exceeds this, the starter will trip on overload or weld its contacts; this is the hard limit for the power circuit. The IP54 enclosure keeps dust and splash out, suitable for machine-mounted installation on a conveyor line or packaging cell, but not for washdown zones (that would need IP65 or higher). The control supply is 20.4 to 26.4 V DC, and the operating voltage for the main circuit spans 340 to 440 V AC at 50/60 Hz. The unit includes a motor brake output for 400 V AC brakes, so if your motor has an AC brake coil, this starter handles it without an external brake rectifier. Its 245 mm width and 205 mm depth mean it occupies roughly the space of two standard contactors side by side; plan for that footprint in your panel layout. Two digital inputs are onboard, so you can wire local pushbuttons or a limit switch directly to the starter without a separate I/O block. The AS-Interface bus handles the communication — no PROFIBUS or PROFINET on this variant, so it stays in the AS-i domain only.","metaTitle":"Siemens 3RK4320-3AQ51-0BA3 SIRIUS MCU Motor Starter","metaDescription":"Siemens SIRIUS 3RK4320-3AQ51-0BA3 motor starter MCU for AS-Interface. Rated 0.63 A at AC-3 400 V, Trip Class 10, IP54. Current lifecycle stage.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"205 mm","Width":"245 mm","title":"3RK4320-3AQ51-0BA3","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 400 V AC (internal) Performance class 0.63 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":"0.63 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":"Yes","brake control with 500 V DC":"No","Type Of The Motor Protection":"bimetal","at AC-3 at 400 V rated value":"0.63 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":"0.2 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","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":"0.45 ... 0.63 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/e0c64090ad55c4a873a1e4da46f0ad59.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=150195&mlfb=3RK4320-3AQ51-0BA3"},"ai":{"faq":[{"question":"What is the replacement or equivalent for 3RK4320-3AQ51-0BA3?","answer":"No official successor is listed for this current-production part. The 3RK4320-3AQ51-0BA3 is the active order code; no replacement is needed."},{"question":"Can 3RK4320-3AQ51-0BA3 be used for direct-on-line starting?","answer":"Yes — the product design is a direct starter, meaning it connects the motor directly to the line without a soft-start or VFD. It is built for across-the-line starting of three-phase induction motors."},{"question":"Is 3RK4320-3AQ51-0BA3 compatible with AS-Interface?","answer":"Yes — the AS-Interface protocol is supported. This motor starter communicates directly on an AS-i network without a separate gateway for the motor control function."},{"question":"What is the price of Siemens 3RK4320-3AQ51-0BA3?","answer":"Pricing is confirmed at quote time against an RFQ. Submit a request for current market pricing through our sourcing desk."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3AQ51-0BA3","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/3RK4320-3AQ51-0BA3 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}