{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1BW44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1BW44","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1BW44","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1BW44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS power contactor, Size S3, 3RT1045-1BW44, 45 kW at 500 V, screw-type terminals, snap-on mounting for 35 mm and 75 mm rail.","salesMarkdown":"## Integrator's first look The Siemens 3RT1045-1BW44 is a Size S3 SIRIUS power contactor rated for 45 kW at 500 V, with a 37 kW rating at AC-2, 400 V. The enclosure carries IP20 on the front with the cover installed; the terminal area itself is IP00, so panel builders need to account for clearance and finger-safe shrouding in the layout. The 45 kW at 500 V rating tells you this contactor is sized for medium motor loads — think 50–60 hp class in 480 V markets. The AC-2 rating of 37 kW at 400 V covers slip-ring motor duty where starting current is moderate. The AC-4 rating of 66 A at 400 V handles reversing or inching duty with higher switching stress. Main circuit terminals accept solid wire in multiple combinations: 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), or max 2x (0.75–4 mm²). For stranded wire, the main terminals take 2x (10–50 mm²). The auxiliary/control terminals accept 2x (2.5–16 mm²) solid or stranded. This range covers everything from control wiring up to the main power feed for a 45 kW motor. The contactor measures 146 mm high, 70 mm wide, and 201 mm deep. Side-by-side mounting is supported, which saves rail space in multi-contactor groups. The screw-and-snap-on mounting works on both 35 mm and 75 mm standard mounting rails — the 75 mm option is useful for high-current panels where the rail needs extra mechanical support. The arcing time of 10–15 ms and DC operating time of 14–20 ms are within typical ranges for coordinating with upstream short-circuit protection. ## Compliance documentation The part carries a RoHS compliance date of 05/01/2012, meaning it meets the EU RoHS directive for substances. As a Siemens SIRIUS product, it is designed to meet IEC/EN 60947-4-1 for contactors and motor starters. UL and CSA listings are standard for this series, though specific file numbers should be confirmed from the nameplate marking on the unit received.","metaTitle":"Siemens 3RT1045-1BW44 SIRIUS Power Contactor, Size S3, 45 kW","metaDescription":"Siemens 3RT1045-1BW44 SIRIUS power contactor, Size S3, 45 kW at 500 V, screw terminals, snap-on 35/75 mm rail. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"201 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)","Width":"70 mm","at DC":"14 ... 20 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","Arcing Time":"10 ... 15 ms","Rated Value":"48 V","On The Front":"IP20; IP20 on the front with cover / box terminal","Initial Value":"0.8","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","Full-Scale Value":"1.1","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 500 V rated value":"45 kW","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","closing power of magnet coil at DC":"15 W","holding power of magnet coil at DC":"15 W","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)","Type Of Voltage Of The Control Supply Voltage":"DC","Required Spacing For Grounded Parts At The Side":"6 mm","contact rating of auxiliary contacts according to UL":"A600 / Q600","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","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":"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":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=69212&mlfb=3RT1045-1BW44","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1BW44/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional second-source to 3RT1045-1BW44?","answer":"The 3RT1044-1FB46 is a Size S2 contactor in the same SIRIUS family, but it has a lower power rating. The 3RT5045-1AC20 and 3RT5046-1BM40 are newer-generation SIRIUS 3RT5 contactors that offer similar ratings in a different frame. For a direct drop-in without rewiring, the 3RT1045-1BW44 is the specific Size S3 variant with screw terminals."},{"question":"What is the depth of 3RT1045-1BW44?","answer":"The depth is 201 mm. Combined with the 146 mm height and 70 mm width, this is a standard Size S3 footprint for panel layout planning."},{"question":"What compliance documentation does Siemens provide for 3RT1045-1BW44?","answer":"The part is RoHS compliant with a substance prohibition date of 05/01/2012. As a SIRIUS contactor, it meets IEC/EN 60947-4-1. UL and CSA certifications are standard for the series; the specific markings appear on the unit nameplate."},{"question":"Where can I buy 3RT1045-1BW44 and how is it quoted?","answer":"This part is sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm quote on your quantity and delivery schedule."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1BW44","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/3RT1045-1BW44 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}}