{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU5146-4KB1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU5146-4KB1","canonicalUrl":"https://aoctrl.com/siemens/3RU5146-4KB1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU5146-4KB1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU5146-4KB1 thermal overload relay, 75 A rated, adjustable 57-75 A, CLASS 10, screw terminals, S3 contactor size.","salesMarkdown":"This one is rated for a continuous 75 A, adjustable from 57 to 75 A via a dial, and it's a CLASS 10 trip, meaning it will open the circuit within 10 seconds at 7.2× the set current. That's the right speed for standard three-phase induction motors starting across the line. The adjustable current range of 57 to 75 A tells you the motor FLA this relay can protect. If your motor nameplate says 65 A, you dial it in. It's a 3-pole relay with screw-type terminals on both the main and auxiliary circuits. The main terminals accept 2x (10 AWG to 1/0) or a single 2/0. The auxiliary contacts take 2x (20 to 16 AWG). Tightening torque on the mains is 4 to 6 N·m — use a torque driver, not a feel. ## Where it goes — panel and environment This relay is designed for stand-alone installation, not DIN-rail snap-on. It mounts directly to the contactor or on a separate base. It needs 6 mm of free air space to grounded parts on the side for cooling. It's built for the SIRIUS S3 contactor frame size. Shock resistance is 8g for 10 ms per IEC 60068-2-27, and surge voltage resistance is 8 kV. Installation altitude is limited to 2 000 m above sea level without derating.","metaTitle":"Siemens 3RU5146-4KB1 Thermal Overload Relay, 57-75 A, CLASS","metaDescription":"Siemens SIRIUS 3RU5146-4KB1 thermal overload relay. Rated 75 A, adjustable 57-75 A, CLASS 10 trip. Screw terminals. Active production. Sourced to order via RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"140 mm","Width":"70 mm","title":"3RU5146-4KB1","Height":"120 mm","at 24 V":"1 A","Per Pole":"6.3 W","at 110 V":"0.22 A","at 230 V":"2 A","Trip Class":"CLASS 10","description":"Overload relay 57...75 A size S3, class 10 for motor protection for individual mounting main circuit: screw connection AUX. circuit: screw connection manual automatic reset","lifecycle_stage":"current","During Operation":"-20 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"stand-alone installation","Mounting Position":"with vertical mounting surface +/-135° rotatable, with vertical mounting surface +/- 45° tiltable to the front and back","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Thermal overload relay","For Main Current Circuit":"screw-type terminals","power loss [W] total typical":"16.5 W","Operating Voltage Rated Value":"1 000 V","Substance Prohibitance (Date)":"07/01/2006","Design Of The Overload Release":"thermal","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"75 A","for AWG cables for main contacts":"2x (10 ... 1/0), 1x (10 ... 2/0)","For Auxiliary And Control Circuit":"screw-type terminals","Relative Humidity During Operation":"0 ... 100 %","Surge Voltage Resistance Rated Value":"8 kV","for AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Number Of Poles For Main Current Circuit":"3","shock resistance according to IEC 60068-2-27":"8g / 10 ms","Required Spacing For Grounded Parts At The Side":"6 mm","Size Of Contactor Can Be Combined Company-Specific":"S3","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 6 A, quick: 10 A","Tightening Torque For Main Contacts With Screw-Type Terminals":"4 ... 6 N·m","insulation voltage with degree of pollution 3 at AC rated value":"1 000 V","power loss [W] for rated value of the current at AC in hot operating state":"18.9 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"57 ... 75 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/50d8bfaa81c425a01e95fbbf700436f8.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=621254&mlfb=3RU5146-4KB1"},"ai":{"faq":[{"question":"What is the adjustable current range?","answer":"The adjustable current response value is 57 to 75 A. You set the dial to match your motor's full-load amps."},{"question":"What trip class is it?","answer":"CLASS 10. It will trip within 10 seconds at 7.2 times the set current, which is standard for general-purpose motor starting."},{"question":"What contactor frame size does it match?","answer":"It's designed for the SIRIUS S3 contactor size. That's the Siemens 3RT7 series in the same frame."},{"question":"What are the terminal specs for the main circuit?","answer":"Screw-type terminals accepting 2x (10 AWG to 1/0) or a single 2/0. Tightening torque is 4 to 6 N·m."},{"question":"Does it have RoHS compliance?","answer":"Yes, the substance prohibition date is July 1, 2006, which aligns with RoHS compliance."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU5146-4KB1","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/3RU5146-4KB1 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}}