{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RK1908-1SK00","brand":"Siemens","brandSlug":"siemens","productSlug":"3RK1908-1SK00","canonicalUrl":"https://aoctrl.com/siemens/3RK1908-1SK00","factsUrl":"https://aoctrl.com/api/mcp/products/3RK1908-1SK00","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIMATIC motor starter kit, 3RK1908-1SK00, reversing starter, PROFIBUS DP and PROFINET, adjustable trip class, 55 kA SCCR at 400 V.","salesMarkdown":"The Siemens 3RK1908-1SK00 is a SIMATIC-branded motor starter kit configured as a reversing starter — meaning it can start a motor in either direction without an external contactor interlock. The unit is pluggable into a BaseUnit, so the power and control wiring stay in the panel while the electronics module swaps out — useful for quick replacement or commissioning changes without pulling wires. The headline rating here is the short-circuit current rating: 55 kA at both 400 V and 500 V. Trip class is adjustable — CLASS OFF, 5, or 10 — so you can match the overload curve to the motor's starting profile. Class 10 is standard for most general-purpose motors; Class 5 for fast-starting loads like pumps; OFF disables the overload function if you're using an external relay. The 4 digital inputs are onboard for local control or feedback, and the unit supports both PROFIBUS DP and PROFINET protocols, so it drops into either a legacy fieldbus or a modern industrial Ethernet architecture without a gateway. Dimensions are 150 mm deep, 30 mm wide, 142 mm tall — the 30 mm width is a single module width on a standard DIN rail, so it fits tight panels where space is at a premium. Clearance above and below the unit is 50 mm each direction for airflow and wiring access. Shock rated to 6g at 11 ms, vibration to 2g up to 500 Hz — suitable for machine-mounted applications near conveyors or presses. No last-time-buy or surplus-channel urgency applies here.","metaTitle":"Siemens 3RK1908-1SK00 SIMATIC Motor Starter, Reversing, 55 k","metaDescription":"Siemens 3RK1908-1SK00 SIMATIC motor starter kit. Reversing starter with PROFIBUS/PROFINET, adjustable trip class, 55 kA SCCR at 400 V. Active production. RFQ for lead time.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Remote I/O & Fieldbus Modules"],"specifications":{"Depth":"150 mm","Width":"30 mm","title":"3RK1908-1SK00","Height":"142 mm","Upwards":"50 mm","Downwards":"50 mm","Safe State":"Load circuit open","Trip Class":"CLASS OFF / 5 / 10 adjustable","description":"ET 200SP MS starter kit including 3RK 1308 motor starter 0.9 - 3 A, reversing starter, BaseUnit with infeed 24 V and 500 V, EMC distance module (blank module 15 mm)","Direct Start":"Yes","During Storage":"-40 ... +70 °C","OFF-delay time":"35 ... 50 ms","lifecycle_stage":"current","During Operation":"-25 ... +60 °C; For derating see manual","During Transport":"-40 ... +70 °C","Fastening Method":"pluggable in BaseUnit","Minimum Load [%]":"20 %","Product Category":"Motor starter","Product Function":"Reversing starter","Reverse Starting":"Yes","Shock Resistance":"6g / 11 ms","Mounting Position":"Vertical, horizontal (observe derating)","On-Site Operation":"Yes","PROFINET protocol":"Yes","Product Brand Name":"SIMATIC","Type Of Assignment":"1","Degree Of Pollution":"2","Maximum Permissible":"28.8 V","Minimum Permissible":"20.4 V","Product Designation":"Starter kit","Overvoltage Category":"III","PROFIBUS DP protocol":"Yes","Vibration Resistance":"15 mm to 6 Hz; 2g to 500 Hz","at 230 V rated value":"0.25 hp","at 400 V rated value":"55 kA","at 500 V rated value":"55 kA","For Main Energy Infeed":"Plug contact to Base Unit","Remote Firmware Update":"Yes","Number Of Digital Inputs":"4","at 200/208 V rated value":"0.5 hp","at 220/230 V rated value":"0.5 hp","at 460/480 V rated value":"1.5 hp","according to IEC 60947-4-2":"AC-53a: 3 A: (8-0,7: 70-32)","1 For Digital Input Signals":"Pluggable module - accessory","Intrinsic Device Protection":"Yes","For Supply Voltage Line-Side":"Plug contact to Base Unit","Type Of The Motor Protection":"solid-state","For Load-Side Outgoing Feeder":"Plug contact to Base Unit","Operating Voltage Rated Value":"48 ... 500 V","Substance Prohibitance (Date)":"03/13/2019","supports PROFIenergy shutdown":"Yes","Insulation Voltage Rated Value":"500 V","Design Of The Switching Contact":"Hybrid","supply voltage at DC rated value":"24 V","Operating Frequency 1 Rated Value":"50 Hz","Operating Frequency 2 Rated Value":"60 Hz","Between Main And Auxiliary Circuit":"500 V","Design Of Short-Circuit Protection":"fuse","Product Function Bus Communication":"Yes","Relative Humidity During Operation":"10 ... 95 %","air pressure according to SN 31205":"900 ... 1 060 hPa","Product Component Motor Brake Output":"No","Surge Voltage Resistance Rated Value":"6 kV","supports PROFIenergy measured values":"Yes","EMC immunity according to IEC 60947-1":"Class A","Type Of Voltage Of The Supply Voltage":"DC","due to burst according to IEC 61000-4-4":"2 kV","duration of inrush current peak at 24 V":"0.145 ms","reference code according to IEC 81346-2":"Q","Number Of Poles For Main Current Circuit":"3","Wire Length For Motor Unshielded Maximum":"200 m","Product Function Short Circuit Protection":"Yes","at 500 V according to UL 60947 rated value":"100 kA","protocol is supported AS-Interface protocol":"No","For Power Supply Reverse Polarity Protection":"Yes","equipment variant according to IEC 60947-4-2":"3","operational current at AC at 400 V rated value":"3 A","EMC emitted interference according to IEC 60947-1":"class A","electrostatic discharge according to IEC 61000-4-2":"8 kV air discharge","Relative Negative Tolerance Of The Operating Frequency":"5 %","Relative Positive Tolerance Of The Operating Frequency":"5 %","Installation Altitude At Height Above Sea Level Maximum":"4 000 m; For derating see manual","conducted HF interference emissions according to CISPR11":"Class A for industrial environment","Relative Symmetrical Tolerance Of The Operating Frequency":"5 %","field-bound HF interference emission according to CISPR11":"Class A for industrial environment","Type Of Electrical Connection Of The Communication Interface":"Plug contact to Base Unit","full-load current (FLA) for 3-phase AC motor at 480 V rated value":"3 A","operating voltage at AC at 60 Hz according to CSA and UL rated value":"480 V","Mechanical Service Life (Operating Cycles) Of The Main Contacts Typical":"30 000 000","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"0.9 ... 3 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/2506c84bc50fd54eb200b0e325c9c833.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1353794&mlfb=3RK1908-1SK00"},"ai":{"faq":[{"question":"What is the short-circuit current rating?","answer":"55 kA at both 400 V and 500 V rated values, meaning it can safely interrupt a fault up to that level without damage."},{"question":"Does it support PROFIBUS and PROFINET?","answer":"Yes, it supports both PROFIBUS DP and PROFINET protocols, so it can be used in either fieldbus or industrial Ethernet networks."},{"question":"What is the trip class and is it adjustable?","answer":"The trip class is adjustable to OFF, 5, or 10, allowing the overload protection curve to be matched to the motor's starting characteristics."},{"question":"What are the mounting dimensions?","answer":"150 mm deep, 30 mm wide (single module width), 142 mm tall. Plugs into a BaseUnit on DIN rail. Requires 50 mm clearance above and below."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RK1908-1SK00","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/3RK1908-1SK00 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}}