{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1025-3KF40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1025-3KF40","canonicalUrl":"https://aoctrl.com/siemens/3RT1025-3KF40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1025-3KF40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, size S0, 3RT1025-3KF40, 110 VDC coil with varistor, screw and snap-on 35 mm DIN rail mount, IP20 front / IP00 terminals.","salesMarkdown":"This contactor is rated for motor duty: 7.5 kW at AC-2 (400 V) and 15.5 A at AC-4 (400 V). AC-2 covers slip-ring motor starting and reversing; AC-4 covers plugging and inching — the harder duty cycle. If you're switching a standard squirrel-cage motor on a pump or conveyor, those are the numbers that tell you whether it'll hold up. At 500 V it's good for 10 kW and at 690 V for 11 kW, so it spans common European voltage levels without derating surprises. The coil is a straight 110 V DC, pulling 4.2 W on both pick-up and hold. That constant-power coil means the control transformer or DC supply doesn't see a current spike on closure — useful when you're driving several contactors from one supply. The varistor across the coil clips the inductive kickback, which protects nearby PLC outputs and keeps the panel quiet. Mechanically, it's rated for 10 million typical operations, which is a long service life for a contactor this size. Side-by-side mounting is allowed, which keeps the panel dense. The main circuit terminals accept solid or stranded wire: 2x (0.25 to 2.5 mm²) for the control circuit, and up to 2x 10 mm² or 1x 8 AWG for the power circuit. That's enough for the motor leads on a 7.5 kW load at 400 V. The front of the contactor is IP20 — safe to touch with tools — but the terminals are IP00, so live parts are exposed once the wire is landed. That's standard for panel-mount contactors; just means the panel door needs to be interlocked or the contactor placed behind a cover. That lets you choose between tighter protection or higher fault tolerance depending on the application.","metaTitle":"Siemens 3RT1025-3KF40 SIRIUS Power Contactor, 110 VDC Coil,","metaDescription":"Siemens 3RT1025-3KF40 SIRIUS power contactor, size S0, 110 VDC coil with varistor, rated 7.5 kW at AC-2 400 V. Current production status. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"100 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"45 mm","Height":"88 mm","Maximum":"2 000 m","At The Side":"6 mm","Rated Value":"110 V","Initial Value":"0.7","Mounting type":"screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Full-scale value":"1.25","Size of contactor":"S0","Product Brand Name":"SIRIUS","Degree of pollution":"3","Product designation":"power contactor","at 24 V rated value":"10 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 220 V rated value":"0.3 A","at 230 V rated value":"6 A","at 400 V rated value":"3 A","at 500 V rated value":"10 kW","at 690 V rated value":"11 kW","Instantaneous Contact":"0","Side-by-side mounting":"Yes","Single Or Multi-Stranded":"2x (1 ... 2,5 mm²), 2x (2,5 ... 6 mm²), max. 2x 10 mm²","at AC-2 at 400 V rated value":"7.5 kW","at AC-4 at 400 V rated value":"15.5 A","Design of the surge suppressor":"with varistor","protection class IP on the front":"IP20","Closing power of magnet coil at DC":"4.2 W","Holding power of magnet coil at DC":"4.2 W","Operating current at AC-12 maximum":"10 A","With Type Of Assignment 2 Required":"fuse gL/gG: 25 A","Protection class IP of the terminal":"IP00","at AWG conductors for main contacts":"2x (16 ... 12), 2x (14 ... 10), 1x 8","With Type Of Coordination 1 Required":"fuse gL/gG: 63 A","Reference code acc. to DIN EN 81346-2":"Q","Number of NC contacts for main contacts":"0","Number of NO contacts for main contacts":"3","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number of poles for main current circuit":"3","at AWG conductors for auxiliary contacts":"2x (24 ... 14)","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","at ambient temperature 40 °C rated value":"40 A","Finely Stranded Without Core End Processing":"2x (0.25 ... 2.5 mm²)","Type of voltage of the control supply voltage":"DC","Type of electrical connection for main current circuit":"screw-type terminals","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","Type of electrical connection for auxiliary and control current circuit":"spring-loaded terminals"}},"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=75793&mlfb=3RT1025-3KF40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1025-3KF40/alternatives.json"},"ai":{"faq":[{"question":"What are the key motor ratings for this contactor?","answer":"At 400 V, it's rated 7.5 kW in AC-2 duty and 15.5 A in AC-4 duty. At 500 V it handles 10 kW, and at 690 V it's good for 11 kW. The coil is 110 V DC with a built-in varistor suppressor."},{"question":"Does the 3RT1025-3KF40 fit on a standard DIN rail?","answer":"Yes, it mounts on a 35 mm standard rail per DIN EN 50022, using either screws or the snap-on clip. Side-by-side mounting is permitted, and the S0 frame is 45 mm wide."},{"question":"What wire sizes does this contactor accept?","answer":"The control circuit terminals accept 2x (0.25 to 2.5 mm²) solid or stranded. The main power terminals accept up to 2x 10 mm² or 1x 8 AWG. For AWG, that's 2x (16 to 12) or 2x (14 to 10) on the main contacts."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1025-3KF40","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/3RT1025-3KF40 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}}