{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1276-6NB36","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1276-6NB36","canonicalUrl":"https://aoctrl.com/siemens/3RT1276-6NB36","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1276-6NB36","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS vacuum contactor, Size S12, 3RT1276-6NB36, 21-27.3 VDC coil, screw-type terminals, 240 mm² main conductor cross-section, 225 × 160 × 214 mm (D×W×H).","salesMarkdown":"The Siemens 3RT1276-6NB36 is a SIRIUS-branded vacuum contactor in the Size S12 frame — the largest of the standard SIRIUS contactor sizes, built for high-cycle motor switching and furnace/transformer loads where contact erosion from arcing is the main wear mechanism. Vacuum interrupters suppress the arc inside a sealed bottle, so the contactor handles AC-3 duty at up to 750 operating cycles per hour without the contact maintenance a conventional air-break contactor needs. Coil pull-in is rated 21–27.3 VDC, screw-type terminals on the magnet coil; the main power circuit accepts stranded cable up to 240 mm² per lug, which puts it in the class for motors in the 200–400 kW range depending on voltage and duty. ## Mounting and panel integration — Size S12 envelope The contactor measures 225 mm deep, 160 mm wide, 214 mm tall. That 225 mm depth is the dimension to check against the back panel or enclosure door clearance — it's deeper than a standard IEC contactor because the vacuum bottle assembly and the arc-chamber stack add axial length. ## Coil and control circuit — screw terminals, DC pick-up The magnet coil uses screw-type terminals, rated 21–27.3 VDC. The coil's initial value factor is 0.8, full-scale value 1.1 — these are the operating tolerances for the control voltage. Auxiliary switch is included (screw-type terminals on the aux block). Control wiring accepts solid or stranded conductors: 2× (0.5–1.5 mm²), 2× (0.75–2.5 mm²), max 2× (0.75–4 mm²).","metaTitle":"Siemens 3RT1276-6NB36 SIRIUS Vacuum Contactor, Size S12, 21-","metaDescription":"Siemens 3RT1276-6NB36 SIRIUS vacuum contactor, Size S12, 21-27.3 VDC coil, 240 mm² main lugs, 750 ops/h AC-3. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"225 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)","Width":"160 mm","at AC":"80 ... 100 ms","at DC":"80 ... 100 ms","Height":"214 mm","Upwards":"10 mm","Forwards":"20 mm","Stranded":"70 ... 240 mm²","at 50 Hz":"0.4","at 60 Hz":"0.4","Downwards":"10 mm","Arcing Time":"10 ... 15 ms","At The Side":"10 mm","Rated Value":"21 ... 27.3 V","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Screw-type terminals","Number Of Holes":"1","at AC-1 maximum":"700 1/h","at AC-2 maximum":"250 1/h","at AC-3 maximum":"750 1/h","at AC-4 maximum":"250 1/h","lifecycle_stage":"current","Auxiliary Switch":"Yes","During Operation":"-25 ... +60 °C","Fastening Method":"screw fixing","Full-Scale Value":"1.1","at AC-3e maximum":"750 1/h","Diameter Of Holes":"11 mm","Mounting Position":"+/-22,5° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface; standing, on horizontal mounting surface","Size Of Contactor":"S12","Solid Or Stranded":"2x (0,5 ... 1,5 mm²), 2x (0,75 ... 2,5 mm²), max. 2x (0,75 ... 4 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Vacuum contactor","at 24 V rated value":"10 A","at 48 V rated value":"2 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 125 V rated value":"0.9 A","at 220 V rated value":"0.3 A","at 230 V rated value":"6 A","at 400 V rated value":"3 A","at 480 V rated value":"477 A","at 50 Hz rated value":"21 ... 27.3 V","at 500 V rated value":"2 A","at 60 Hz rated value":"21 ... 27.3 V","at 600 V rated value":"472 A","at 690 V rated value":"1 A","Side-By-Side Mounting":"Yes","at 1000 V rated value":"710 kW","For Auxiliary Contacts":"18 ... 14","Width Of Connection Bar":"25 mm","For Main Current Circuit":"Connection bar","at 200/208 V rated value":"150 hp","at 220/230 V rated value":"200 hp","at 460/480 V rated value":"400 hp","at 575/600 V rated value":"500 hp","Relative Humidity Minimum":"10 %","Of Main Circuit Rated Value":"8 kV","Thickness Of Connection Bar":"6 mm","at AC-3 rated value maximum":"1 000 V","at AC in hot operating state":"96 W","at AC-3e rated value maximum":"1 000 V","at AC-4 at 400 V rated value":"430 A","safety-related switching OFF":"Yes","Substance Prohibitance (Date)":"05/01/2012","Design Of The Surge Suppressor":"with varistor","Of Auxiliary Circuit Rated Value":"6 kV","For Auxiliary And Control Circuit":"screw-type terminals","Function Module For Communication":"No","With Type Of Assignment 2 Required":"gG: 800 A (690 V, 50 kA), aM: 630 A (690 V, 50 kA), BS88: 800 A (415 V, 50 kA)","Without Load Current Share Typical":"3.6 W","closing power of magnet coil at DC":"800 W","holding power of magnet coil at DC":"3.6 W","At Contactor For Auxiliary Contacts":"Screw-type terminals","With Type Of Coordination 1 Required":"gG: 800 A (690 V, 100 kA)","at AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14), 1x 12","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"32 W","number of NO contacts for main contacts":"3","reference code according to IEC 81346-2":"Q","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","voltage at PLC-control input rated value":"24 V","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes","Type Of Voltage Of The Control Supply Voltage":"AC/DC","type of PLC-control input according to IEC 60947-1":"Type 2","contact rating of auxiliary contacts according to UL":"A600 / Q600","Of Main Circuit With Degree Of Pollution 3 Rated Value":"1 000 V","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","operating range factor of the voltage at PLC-control input":"0.8 ... 1.1","Of Auxiliary Circuit With Degree Of Pollution 3 Rated Value":"500 V","For Short-Circuit Protection Of The Auxiliary Switch Required":"gG: 10 A (500 V, 1 kA)","minimum cross-section in main circuit at maximum AC-1 rated value":"370 mm²","number of NC contacts for auxiliary contacts instantaneous contact":"2","number of NO contacts for auxiliary contacts instantaneous contact":"2","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/5c6a207110fd40132f03c49d85f8da29.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=110067&mlfb=3RT1276-6NB36","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1276-6NB36/alternatives.json"},"ai":{"faq":[{"question":"What is the 3RT1276-6NB36 rated for in AC-3 duty?","answer":"The contactor is rated for up to 750 operating cycles per hour in AC-3 (motor switching) duty, which is the standard mechanical endurance rating for the Size S12 vacuum-contactor frame."},{"question":"What size cable does the main power circuit accept?","answer":"The main lugs accept stranded cable from 70 mm² up to 240 mm² — sized for high-current motor feeders or transformer primary circuits."},{"question":"What is the depth of the 3RT1276-6NB36?","answer":"The depth is 225 mm, which is the dimension to verify for enclosure clearance — the vacuum-bottle assembly makes this deeper than a standard air-break contactor of similar rating."},{"question":"Where can I buy the 3RT1276-6NB36?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at the time of quotation."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1276-6NB36","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/3RT1276-6NB36 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}}