{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1025-3KB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1025-3KB40","canonicalUrl":"https://aoctrl.com/siemens/3RT1025-3KB40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1025-3KB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, 3RT1025-3KB40, S0 size, 24 VDC coil, screw-type main terminals, spring-loaded auxiliary terminals, IP20 front, current production.","salesMarkdown":"## SIRIUS power contactor, S0 frame, 24 VDC coil The coil is rated at 24 VDC with a closing power of 4.2 W and holding power of 4.2 W — a continuous-duty solenoid that stays cool at steady state. Main contacts are screw-type terminals; auxiliary and control circuit connections use spring-loaded terminals for faster wiring. ## Motor switching and coordination For AC-2 duty at 400 V, this contactor is rated at 7.5 kW motor power; for AC-4 at 400 V, the rated operational current is 15.5 A — the figure that governs reversing or inching applications where the contacts make and break under load. Short-circuit coordination is specified: with type 2 coordination, a gL/gG fuse of 25 A is required; with type 1 coordination, a 63 A gL/gG fuse. That means the contactor can be paired with a 25 A fuse for coordinated protection that leaves the contactor serviceable after a fault, or a 63 A fuse for basic protection where the contactor may need replacement. Side-by-side mounting is permitted — no derating required for zero-gap adjacent installation. This makes it suitable for industrial control panels in factory environments, not for outdoor or washdown locations without additional enclosure.","metaTitle":"Siemens 3RT1025-3KB40 SIRIUS Power Contactor, 24 VDC, S0 Siz","metaDescription":"Siemens 3RT1025-3KB40 SIRIUS power contactor, 24 VDC coil, S0 frame, screw-type main terminals, spring-loaded aux terminals. IP20 front, current production. Sourced to order agains","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","Rated Value":"24 V","On The Front":"IP20","Initial Value":"0.7","Of The Terminal":"IP00","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022","Full-Scale Value":"1.25","Size Of Contactor":"S0","Solid Or Stranded":"2x (1 ... 2,5 mm²), 2x (2,5 ... 6 mm²), max. 2x 10 mm²","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","Side-By-Side Mounting":"Yes","For Main Current Circuit":"screw-type terminals","at AC-2 at 400 V rated value":"7.5 kW","at AC-4 at 400 V rated value":"15.5 A","Substance Prohibitance (Date)":"01.07.2006 00:00:00","Design Of The Surge Suppressor":"with varistor","at AWG cables for main contacts":"2x (16 ... 12), 2x (14 ... 10), 1x 8","For Auxiliary And Control Circuit":"spring-loaded terminals","With Type Of Assignment 2 Required":"fuse gL/gG: 25 A","closing power of magnet coil at DC":"4.2 W","holding power of magnet coil at DC":"4.2 W","reference code acc. to IEC 81346-2":"Q","With Type Of Coordination 1 Required":"fuse gL/gG: 63 A","at AWG cables for auxiliary contacts":"2x (24 ... 14)","operational current at AC-12 maximum":"10 A","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","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","Finely Stranded Without Core End Processing":"2x (0.25 ... 2.5 mm²)","Type Of Voltage Of The Control Supply Voltage":"DC","Required Spacing For Grounded Parts At The Side":"6 mm","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","number of NC contacts for auxiliary contacts instantaneous contact":"0","number of NO contacts for auxiliary contacts instantaneous contact":"0"}},"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=112165&mlfb=3RT1025-3KB40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1025-3KB40/alternatives.json"},"ai":{"faq":[{"question":"What is the coil voltage and power draw for 3RT1025-3KB40?","answer":"The coil is rated at 24 VDC, with a closing power of 4.2 W and holding power of 4.2 W — a continuous-duty solenoid."},{"question":"What are the motor switching ratings for 3RT1025-3KB40?","answer":"For AC-2 duty at 400 V, it is rated at 7.5 kW motor power; for AC-4 at 400 V, the rated operational current is 15.5 A."},{"question":"Where can I buy 3RT1025-3KB40 and how is it quoted?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What is the depth of 3RT1025-3KB40?","answer":"The depth is 100 mm."},{"question":"What solid conductor sizes does the auxiliary terminal accept?","answer":"The spring-loaded auxiliary terminals accept solid conductors of 2x (0.25... 2.5 mm²)."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1025-3KB40","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/3RT1025-3KB40 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}}