{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1AM20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1AM20","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1AM20","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AM20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, 3RT1045-1AM20, Size S3, 208 V 50/60 Hz coil, screw-type terminals, 45 kW at 500 V, snap-on 35/75 mm rail.","salesMarkdown":"The 3RT1045-1AM20: Screw-type terminals on the main circuit accept stranded wire up to 2x 50 mm², and the control circuit handles solid wire from 0.5 to 4 mm². That means no crimping surprises on site — standard screwdriver work. Snap-on mounting onto 35 mm or 75 mm DIN rail, with side-by-side mounting allowed, so it fits tight in a retrofit panel without extra spacing. The AC-3 switching rate of 1000 operations per hour tells you this contactor is built for frequent starting of squirrel-cage motors — think conveyors or pumps cycling every few seconds. AC-4 at 300/h covers plugging or inching duty. If your application is purely resistive heating (AC-1), it'll handle 900/h. Pollution degree 3 means conductive pollution is expected — typical for an unsealed industrial panel near machining or dust. The IP20 front face protects against finger contact, but the terminals are IP00, so the contactor needs to live inside an enclosure, not out in the weather. Mechanical life of 10 million cycles is the mechanical endurance — the electrical life will be lower depending on load, but it's not a part you'll wear out quickly on a standard motor start. Power dissipation of 37 W at 1000 V is the heat it dumps into the panel. If you're packing several of these side-by-side, factor that into your cooling calc — don't just assume the panel fan handles it. The 3RT1045-1AM20 is part of the SIRIUS family, which has broad cross-compatibility within the Size S3 frame. If you're replacing a 3RT1044-1FB46 (a different coil voltage variant), the mechanical footprint and terminal layout are the same — just verify your control voltage matches the 208 V 50/60 Hz coil on this unit.","metaTitle":"Siemens SIRIUS 3RT1045-1AM20 Power Contactor, Size S3, 208 V","metaDescription":"Siemens SIRIUS 3RT1045-1AM20 power contactor, Size S3, 208 V 50/60 Hz coil, screw terminals, 45 kW at 500 V, snap-on DIN rail. Current lifecycle stage. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"139 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)","Width":"70 mm","at AC":"10 ... 25 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","at 50 Hz":"0.8 ... 1.1","at 60 Hz":"0.85 ... 1.1","Arcing Time":"10 ... 15 ms","On The Front":"IP20; IP20 on the front with cover / box terminal","1 Rated Value":"50 Hz","2 Rated Value":"60 Hz","During Storage":"-55 ... +80 °C","Of The Terminal":"IP00","at AC-1 maximum":"900 1/h","at AC-2 maximum":"400 1/h","at AC-3 maximum":"1 000 1/h","at AC-4 maximum":"300 1/h","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm and 75 mm standard mounting rail","Size Of Contactor":"S3","Solid Or Stranded":"2x (2.5 ... 16 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 50 Hz rated value":"208 V","at 500 V rated value":"45 kW","at 60 Hz rated value":"208 V","at 690 V rated value":"21.1 kW","Side-By-Side Mounting":"Yes","at 1000 V rated value":"37 W","For Main Current Circuit":"screw-type terminals","at AC-2 at 400 V rated value":"37 kW","at AC-4 at 400 V rated value":"66 A","Substance Prohibitance (Date)":"05/01/2012","at 40 °C minimum permissible":"50 mm²","at 60 °C minimum permissible":"35 mm²","Insulation Voltage Rated Value":"1 000 V","at 230 V at 60 °C rated value":"38 kW","at 690 V at 60 °C rated value":"114 kW","at 1000 V at 60 °C rated value":"82 W","at AWG cables for main contacts":"2x (10 ... 1/0)","For Auxiliary And Control Circuit":"screw-type terminals","With Type Of Assignment 2 Required":"fuse gL/gG: 160 A","Surge Voltage Resistance Rated Value":"6 kV","With Type Of Coordination 1 Required":"fuse gL/gG: 250 A","at AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14), 1x 12","operational current at AC-12 maximum":"10 A","number of NC contacts for main contacts":"0","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","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","Thermal Short-Time Current Limited To 10 S":"760 A","Finely Stranded Without Core End Processing":"2x (10 ... 35 mm²)","apparent holding power of magnet coil at AC":"27 VA","apparent pick-up power of magnet coil at AC":"298 VA","Type Of Voltage Of The Control Supply Voltage":"AC","Required Spacing For Grounded Parts At The Side":"6 mm","contact rating of auxiliary contacts according to UL":"A600 / Q600","Inductive Power Factor With Closing Power Of The Coil":"0.7","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Inductive Power Factor With The Holding Power Of The Coil":"0.29","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","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","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":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=253181&mlfb=3RT1045-1AM20","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1AM20/alternatives.json"},"ai":{"faq":[{"question":"What are the main power ratings for this contactor?","answer":"It switches motor loads up to 45 kW at 500 V and 21.1 kW at 690 V, with a 208 V 50/60 Hz coil. Mechanical life is 10 million operations."},{"question":"Will the 3RT1045-1AM20 drop into a panel designed for a 3RT1044-1FB46?","answer":"Mechanically yes — both are Size S3 with the same DIN-rail footprint and screw-terminal layout. The difference is the coil voltage: this unit is 208 V 50/60 Hz, so check your control transformer before swapping."},{"question":"What wire sizes does the screw terminal accept?","answer":"Main circuit stranded: 2x (10 to 50 mm²). Control circuit solid: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²)."},{"question":"What is the IP rating and pollution degree?","answer":"IP20 on the front face (finger-safe), IP00 at the terminals. Pollution degree 3 — suitable for industrial environments with conductive dust or moisture, but must be enclosed."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1AM20","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/3RT1045-1AM20 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}}