{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"LR3D1521","brand":"Schneider Electric","brandSlug":"schneider","productSlug":"LR3D1521","canonicalUrl":"https://aoctrl.com/schneider/LR3D1521","factsUrl":"https://aoctrl.com/api/mcp/products/LR3D1521","rawCanonicalId":null},"summary":{"shortDescription":"Schneider Electric TeSys LRD thermal overload relay, LR3D1521, 12-18 A adjustment range, Class 20, 1 NO + 1 NC auxiliary contacts, obsolete status.","salesMarkdown":"The Schneider Electric LR3D1521 is a non-differential thermal overload relay from the TeSys LRD series, designed for motor protection in control panels. It provides adjustable thermal protection from 12 to 18 A with a Class 20 tripping curve, meaning it allows a 20-second hot-start locked-rotor withstand — standard for general-purpose induction motors driving pumps, fans, and conveyors. The relay offers phase-failure sensitivity: it trips at 130 % of the set current (Ir) on two phases when the third drops to zero, preventing single-phasing damage. Auxiliary contacts are 1 NO + 1 NC, rated 1.5 A at 240 V AC-15 for signalling circuits and 0.1 A at 250 V DC-13. If a direct replacement is needed, a parametric search within the TeSys LRD family for a 12-18 A thermal overload relay with Class 20 and 1 NO + 1 NC contacts is the practical next step, but pin-to-pin compatibility must be verified against the panel wiring and contactor interface. Dimensions are 45 mm wide by 92 mm deep, fitting a standard 45 mm modular envelope. Screw-clamp terminals accept power circuit conductors up to 10 mm² flexible without cable end, and control circuit conductors up to 2.5 mm². IP20 finger-safe protection is provided per IEC 60529, suitable for enclosed panel installation. The LR3D1521 carries multiple international standards: EN/IEC 60947-4-1 and -5-1 for contactors and control-circuit devices, UL 60947-4-1 and -5-1, CSA C22.2 No 60947-4-1 and -5-1, plus GB/T 14048.4 and.5 for the Chinese market. Rated insulation voltage (Ui) is 600 V for UL/CSA and 690 V for IEC. Impulse withstand voltage (Uimp) is 6 kV. Flame retardance is V1 per UL 94. Dielectric strength tested at 1.89 kV at 50 Hz per IEC 60947-1. The relay withstands 6 Gn vibration and 15 Gn shock per IEC 60068-2-6 and -2-7.","metaTitle":"Schneider LR3D1521 TeSys thermal overload relay, 12-18 A, ob","metaDescription":"Schneider Electric LR3D1521 TeSys LRD thermal overload relay, 12-18 A adjustment range, Class 20, 1 NO+1 NC. Obsolete — sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Overload Relays"],"specifications":{"Depth":"3.6 in (92 mm)","Range":"TeSys","Width":"1.8 in (45 mm)","Category":"22314-**OBS**CTR,D-LINE,OVERLOADS","Standards":"EN/IEC 60947-4-1 EN/IEC 60947-5-1 UL 60947-4-1 UL 60947-5-1 CSA C22.2 No 60947-4-1 CSA C22.2 No 60947-5-1 GB/T 14048.4 GB/T 14048.5","Control type":"Red push-button stop Blue push-button reset","Network type":"AC DC","Product name":"TeSys LRD","lifecycle_stage":"current","Flame retardance":"V1 conforming to UL 94","Mounting support":"Plate, with specific accessories Rail, with specific accessories Under contactor","Device short name":"LR3D","Network Frequency":"0...400 Hz","Relay application":"Motor protection","Tightening torque":"Control circuit 15.05 lbf.in (1.7 N.m) screw clamp terminals Power circuit 16.37 lbf.in (1.85 N.m) screw clamp terminals","Tripping threshold":"1.14 +/- 0.06 Ir IEC 60947-4-1","Dielectric strength":"1.89 kV 50 Hz IEC 60947-1","Permissible current":"1.5 A 240 V AC-15 signalling circuit 0.1 A 250 V DC-13 signalling circuit","Mechanical robustness":"Vibrations6 Gn IEC 60068-2-6 Shocks15 Gn for 11 ms IEC 60068-2-7","Associated fuse rating":"4 A gG for signalling circuit 4 A BS for signalling circuit","Thermal overload class":"Class 20 IEC 60947-4-1","Connections - terminals":"Control circuit screw clamp terminals 2 0.002...0.004 in² (1...2.5 mm²) flexible without cable end Control circuit screw clamp terminals 2 0.002...0.004 in² (1...2.5 mm²) flexible with cable end Control circuit screw clamp terminals 2 0.002...0.004 in² (1...2.5 mm²) solid without cable end Power circuit screw clamp terminals 1 0.002...0.02 in² (1.5...10 mm²) flexible without cable end Power circuit screw clamp terminals 1 0.002...0.006 in² (1...4 mm²) flexible with cable end Power circuit screw clamp terminals 1 0.002...0.009 in² (1...6 mm²) solid without cable end","IP degree of protection":"IP20 conforming to IEC 60529","Temperature compensation":"-4...140 °F (-20...60 °C)","Phase failure sensitivity":"Tripping current 130 % of Ir on two phase, the last one at 0","Product or Component Type":"Non differential thermal overload relay","Auxiliary contact composition":"1 NO + 1 NC","[Ui] rated insulation voltage":"Power circuit 600 V CSA Power circuit 600 V UL Power circuit 690 V IEC 60947-4-1","[Ue] rated operational voltage":"690 V AC 0...400 Hz power circuit IEC 60947-4-1","Ambient Air Temperature for Storage":"-76...158 °F (-60...70 °C)","Thermal protection adjustment range":"12...18 A","Ambient air temperature for operation":"-4...140 °F (-20...60 °C) without derating IEC 60947-4-1","[Uimp] rated impulse withstand voltage":"6 kV","[Ith] conventional free air thermal current":"5 A signalling circuit"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/abe75c23b2baccdf61d3f26378860f8c.pdf","sourceUrl":"https://www.se.com/vn/en/product/LR3D1521/tesys-lrd-thermal-overload-relays-12-18-a-class-20/","alternativesUrl":"https://aoctrl.com/api/mcp/products/LR3D1521/alternatives.json"},"ai":{"faq":[{"question":"What replaces the LR3D1521?","answer":"No official successor order code is listed. A direct replacement would need to be selected from the current TeSys LRD range with the same 12-18 A adjustment range, Class 20, and 1 NO + 1 NC contact configuration, but mechanical and wiring compatibility with the specific contactor must be confirmed."},{"question":"What is the thermal adjustment range of the LR3D1521?","answer":"The thermal protection adjustment range is 12 to 18 A."},{"question":"What standards does the LR3D1521 comply with?","answer":"It complies with EN/IEC 60947-4-1, EN/IEC 60947-5-1, UL 60947-4-1, UL 60947-5-1, CSA C22.2 No 60947-4-1, CSA C22.2 No 60947-5-1, GB/T 14048.4, and GB/T 14048.5."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/schneider/LR3D1521","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/schneider/LR3D1521 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}}