{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK4320-3DQ51-0BA2","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK4320-3DQ51-0BA2","canonicalUrl":"https://aoctrl.com/siemens/3RK4320-3DQ51-0BA2","factsUrl":"https://aoctrl.com/api/mcp/products/3RK4320-3DQ51-0BA2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RK4320-3DQ51-0BA2 motor starter, direct starter design, AS-Interface bus communication, 1.25 A rated current at 400 V AC-3, CLASS 10 trip, IP54, DC control supply 20.4...26.4 V.","salesMarkdown":"## What is the 3RK4320-3DQ51-0BA2 and where is it used? It integrates motor protection, switching, and bus communication into one unit, so it replaces a separate contactor, overload relay, and gateway for small motor loads on an AS-Interface line. Rated 1.25 A at 400 V in AC-3 duty (switching motor loads), it is sized for fractional-horsepower motors — pumps, small conveyors, or valve actuators — where the CLASS 10 bimetal overload gives fast trip under locked-rotor conditions. The 1.25 A AC-3 rating at 400 V is the motor-switching current — not the resistive (AC-1) rating. For a 400 V three-phase motor, this typically covers a 0.37 kW (0.5 HP) load. If your motor draws more, this starter will trip on overload or fail to break the stalled current. The 20.4...26.4 V DC control supply powers the electronics and the integrated motor brake output (if used). The brake output is rated for a DC brake — no brake control for 180 V DC or 400 V AC is built in, so external brake switching is needed for those voltages. Two digital inputs are available on the unit for local pushbuttons or limit switches, reducing wiring back to the PLC. The AS-Interface bus carries the I/O and control data over a single two-wire cable. Dimensions are 245 mm wide × 215 mm high × 205 mm deep. Plan for side clearance to route the AS-Interface cable and the motor power wires; the IP54 housing needs no extra air gap for cooling. Short-circuit protection is provided by an upstream circuit breaker (not a fuse) — the starter itself is not a stand-alone breaker.","metaTitle":"Siemens 3RK4320-3DQ51-0BA2 SIRIUS Motor Starter","metaDescription":"Siemens SIRIUS 3RK4320-3DQ51-0BA2 motor starter for AS-Interface. Rated 1.25 A AC-3 at 400 V, CLASS 10 trip, IP54. Current lifecycle stage. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"205 mm","Width":"245 mm","title":"3RK4320-3DQ51-0BA2","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 230 V AC (internal) Performance class 1.25 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":"1.25 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":"1.25 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":"0.4 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":"0.9 ... 1.25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/8aae685378c74785a1f69db6878dd375.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=417787&mlfb=3RK4320-3DQ51-0BA2"},"ai":{"faq":[{"question":"Where can I buy the 3RK4320-3DQ51-0BA2?","answer":"This part is sourced to order through our independent distribution channel. Submit an RFQ for current pricing, stock availability, and lead time. Volume and blanket-order quotes are handled on request."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK4320-3DQ51-0BA2","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/3RK4320-3DQ51-0BA2 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}}