{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU5146-4KB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU5146-4KB0","canonicalUrl":"https://aoctrl.com/siemens/3RU5146-4KB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU5146-4KB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU5146-4KB0, adjustable 57-75 A, Trip Class 10, for S3 contactor mounting, screw terminals.","salesMarkdown":"The Siemens 3RU5146-4KB0 is a SIRIUS thermal overload relay with an adjustable current range of 57-75 A and Trip Class 10 protection. It mounts onto a S3-size contactor with screw-type terminals. The 57-75 A adjustable range covers motor FLA from roughly 57 A up to 75 A. At the top end, that's a 37 kW motor on 400 V three-phase or a 50 hp motor on 480 V. The 75 A continuous rating is the thermal current — the relay must see that current through its power poles, so verify the main circuit wiring: the screw terminals accept 2x (10 AWG to 1/0 AWG) or single 2/0 AWG. Torque them to 4-6 N·m. The 16.5 W typical power loss is dissipated inside the enclosure — factor that into panel thermal calculations if you're packing multiple starters in a sealed cabinet. Trip Class 10 is standard for general-purpose induction motors. The thermal bimetal design is rated for -20 to +70 °C operating ambient and 0-100% RH. This relay snaps onto a SIRIUS S3 contactor — no separate DIN-rail footprint needed. The fastening method is contactor mounting, meaning it plugs directly into the contactor's load-side terminals and is mechanically latched. The mounting position allows ±135° rotation from vertical and ±45° tilt front/back, so you can orient the starter assembly to fit tight enclosures. Required spacing to grounded parts at the side is 6 mm. Depth is 140 mm, width 70 mm, height 120 mm — the depth is the dimension that extends forward from the contactor face, so check your enclosure depth with the contactor plus this relay. ## Sourcing note This is a current-production Siemens SIRIUS part, widely used across European and North American panel builds. The 57-75 A range and Class 10 trip cover a common motor protection band. Same part, different passport: a genuine Siemens relay regardless of which authorized region it originated from.","metaTitle":"Siemens 3RU5146-4KB0 SIRIUS Thermal Overload Relay, 57-75 A,","metaDescription":"Siemens 3RU5146-4KB0 SIRIUS thermal overload relay, adjustable 57-75 A, Trip Class 10. Current production. Sourced to order against RFQ. RoHS compliant.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"140 mm","Width":"70 mm","title":"3RU5146-4KB0","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 mounting onto contactors main circuit: screw terminal AUX. circuit: screw terminal manual automatic reset","lifecycle_stage":"current","During Operation":"-20 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"Contactor mounting","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","at 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","at 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/e236dca5f07400f77116f480dc7ef4e7.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=621252&mlfb=3RU5146-4KB0"},"ai":{"faq":[{"question":"Will 3RU5146-4KB0 drop into a panel specified around 3RT5046-1AM00?","answer":"Yes, the 3RU5146-4KB0 is designed to mount directly onto a S3-size contactor, which includes the 3RT5046-1AM00. The mechanical latch and terminal alignment are identical — no rewiring of the contactor side is needed. The relay's 140 mm depth adds to the contactor's depth, so verify enclosure clearance."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU5146-4KB0","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/3RU5146-4KB0 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}}