{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3FR51-0BA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3FR51-0BA0","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3FR51-0BA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3FR51-0BA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS MCU motor starter for AS-Interface, 3RK4320-3FR51-0BA0, direct starter, 2 A AC-3 at 400 V, IP55, Class 10, 340-440 V AC operating voltage, 20.4-26.4 V DC control supply.","salesMarkdown":"## SIRIUS MCU motor starter for AS-Interface networks The Siemens 3RK4320-3FR51-0BA0 is a SIRIUS MCU motor starter designed for direct-on-line starting of three-phase motors over an AS-Interface bus. It integrates the motor protection, switching, and AS-i communication into a single IP55-rated enclosure, eliminating separate contactor, overload relay, and gateway wiring. The Class 10 bimetal overload protects against sustained overcurrents typical of stalled rotor conditions. Operating voltage is 340 to 440 V AC at 50/60 Hz, with a DC control supply of 20.4 to 26.4 V DC for the AS-Interface bus power and logic. ## AS-Interface integration and mounting This motor starter communicates natively via the AS-Interface protocol — no PROFIBUS or PROFINET onboard. Mounting is flexible: the 182 mm wide, 220 mm tall, 145 mm deep enclosure can be rotated ±180° on a vertical surface and tilted forward or backward by ±22.5°. That range covers most panel layouts where a flat mounting plate or machine frame is available. IP55 protection means it's dust-protected and can handle low-pressure water jets — suited for machine-mounting in environments with occasional washdown or condensation, though not for submersion or high-pressure cleaning. ## Motor protection and short-circuit coordination The bimetal overload relay inside provides Class 10 trip protection. Short-circuit protection is handled by upstream circuit breakers (the starter itself does not include a built-in breaker). The design supports Type 1 or Type 2 coordination depending on the upstream breaker selected; Siemens publishes coordination tables for the SIRIUS family.","metaTitle":"Siemens 3RK4320-3FR51-0BA0 SIRIUS MCU Motor Starter","metaDescription":"Siemens SIRIUS 3RK4320-3FR51-0BA0 motor starter for AS-Interface. Rated 2 A AC-3 at 400 V, IP55, Class 10. Currently in production.","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":"2 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":"2 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":"0.8 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","maximum short-circuit current breaking capacity (Icu) at 400 V rated value":"50 000 A","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"1.4 ... 2 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=80913&mlfb=3RK4320-3FR51-0BA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3FR51-0BA0/alternatives.json"},"ai":{"faq":[{"question":"Is the Siemens 3RK4320-3FR51-0BA0 compatible with AS-Interface?","answer":"Yes, it communicates natively over AS-Interface. The protocol is supported onboard — no additional communication module is required for AS-i networks."},{"question":"What degree of protection does the 3RK4320-3FR51-0BA0 have?","answer":"IP55, meaning dust-protected and protected against low-pressure water jets from any direction. Suitable for machine-mounting in industrial environments with occasional washdown."},{"question":"Where can I buy the Siemens 3RK4320-3FR51-0BA0 with stock in the US?","answer":"This part is sourced to order against your RFQ. Availability and pricing are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3FR51-0BA0","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/3RK4320-3FR51-0BA0 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}}