{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-1BE44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-1BE44","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-1BE44","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1BE44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS S3 power contactor, 3RT1045-1BE44, screw-type terminals, 66 A AC-3 at 400 V, 37 kW rated motor power, 70 x 146 x 201 mm, IP20 front.","salesMarkdown":"The Siemens 3RT1045-1BE44 is a SIRIUS S3-size power contactor — the workhorse for switching three-phase motors up to 37 kW at 400 V AC-3 duty. That AC-3 rating of 66 A is the number that matters for most motor-starting applications: it covers induction motors with moderate inrush, the kind you find on pumps, fans, and compressors on a production line. The AC-1 rating (resistive loads) and AC-4 rating (plugging/inching) are lower, so if your load is a heater bank or a reversing application, the contactor still fits but the thermal capacity shrinks accordingly. The 201 mm depth is the full body dimension; make sure your enclosure depth clears that before you cut the gland plate. Main circuit terminals are screw-type, sized for stranded conductors from 2x (10... 50 mm²) — that's a big lug range, covering everything from a 4 mm² motor feed up to a 50 mm² bus drop. The control circuit (coil and aux) takes solid wire 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²). If you're landing a 50 mm² cable on the line side, you'll need a torque screwdriver; no push-in spring here. The IP20 rating on the front means the terminals are touch-safe once the cover is on, but the terminal body itself is IP00 — don't let loose strands bridge to the panel. ## Coil and switching performance That's a fast, clean make-and-break for a contactor this size. The rated switching frequency at AC-3 is 1 000 operations per hour — fine for a conveyor or pump cycling every few seconds, but if you're doing high-speed jogging, the AC-4 limit of 300 ops/hour is the one to watch. ## Environmental and mounting conditions In practice, that means it's fine in a ventilated industrial panel but not for direct washdown zones unless enclosed.","metaTitle":"Siemens 3RT1045-1BE44 SIRIUS Power Contactor, S3, 66 A AC-3,","metaDescription":"Siemens 3RT1045-1BE44 SIRIUS S3 power contactor, 66 A AC-3 at 400 V, 37 kW motor rating. Screw terminals, DIN-rail mount. Current production. Quoted to order.","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":"60 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=8549&mlfb=3RT1045-1BE44","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-1BE44/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RT1045-1BE44 and get a price?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."},{"question":"What is the closest functional second-source to 3RT1045-1BE44?","answer":"The 3RT1044-1FB46 is a nearby sibling in the same SIRIUS family, but it's a different frame size — the 3RT1044 is an S2, not an S3. The 3RT1045-1BE44 is the S3 version with higher AC-3 current (66 A vs the S2's lower rating). They share the same screw-terminal design and DIN-rail mount, but the S3 is physically larger (70 mm vs 55 mm wide) and carries more motor power. If your panel was laid out for an S2, the S3 won't drop in without moving the rail position or checking the depth clearance."},{"question":"What compliance documentation does Siemens provide for 3RT1045-1BE44?","answer":"Siemens provides standard compliance documentation including RoHS and REACH declarations, UL and IEC certifications, and a CE declaration of conformity. The substance prohibition date (RoHS) on file is May 1, 2012, covering the EU RoHS recast. Full documentation is available through Siemens Industry Online Support."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-1BE44","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/3RT1045-1BE44 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}}