{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB1246-1QM21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB1246-1QM21","canonicalUrl":"https://aoctrl.com/siemens/3RB1246-1QM21","factsUrl":"https://aoctrl.com/api/mcp/products/3RB1246-1QM21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RB12 solid-state overload relay, 6.3 to 25 A, 220-240 VAC 50/60 Hz, integrated thermistor protection, internal earth-fault detection, bistable outputs.","salesMarkdown":"The Siemens 3RB1246-1QM21 is a solid-state overload relay from the SIRIUS 3RB12 family, designed to protect motors against overload, thermistor overtemperature, and earth faults in a single package. It covers a current range of 6.3 to 25 A on a 220 to 240 VAC 50/60 Hz control supply. The unit integrates three protection functions: overload monitoring via the solid-state trip curve, thermistor motor protection (PTC sensor input), and internal earth-fault detection. It provides bistable outputs — 1NO/1NC for the overload/thermistor channel and a separate 1NO/1NC for the earth-fault channel — meaning the relay latches its state after a trip and requires a manual or remote reset, which is standard for safety-critical motor circuits. Mounts on a DIN rail in the motor starter assembly, typically paired with a SIRIUS 3RT contactor. The solid-state design eliminates the mechanical wear of bimetal relays, making it suitable for frequent switching or vibration-prone installations like conveyor lines or compressor skids. The 220-240 VAC control supply is drawn from the motor circuit, so verify the control transformer taps before wiring.","metaTitle":"Siemens 3RB1246-1QM21 Solid-State Overload Relay, 6.3-25 A","metaDescription":"Siemens 3RB1246-1QM21 solid-state overload relay, current production. 6.3 to 25 A, 220-240 VAC, integrated thermistor protection and earth-fault detection. Sourced to order against","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=483198&mlfb=3RB1246-1QM21","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RB1246-1QM21/alternatives.json"},"ai":{"faq":[{"question":"What protection functions does this relay integrate?","answer":"It combines solid-state overload protection (6.3 to 25 A), integrated thermistor motor protection via PTC sensor input, and internal earth-fault detection. Outputs are bistable: 1NO/1NC for overload/thermistor and a separate 1NO/1NC for earth fault."},{"question":"What control voltage does the 3RB1246-1QM21 require?","answer":"The control supply is 220 to 240 VAC, 50/60 Hz. This powers the internal electronics and the bistable output relays."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB1246-1QM21","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/3RB1246-1QM21 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}}