{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1045-3BB44-3MA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1045-3BB44-3MA0","canonicalUrl":"https://aoctrl.com/siemens/3RT1045-3BB44-3MA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3BB44-3MA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT1045-3BB44-3MA0, size S3 power contactor, 37 kW AC-2 at 400 V, 66 A AC-4, screw-type terminals, 24 V DC coil, IP20 front.","salesMarkdown":"## What This Contactor Delivers on the Line The Siemens 3RT1045-3BB44-3MA0 is a SIRIUS size S3 power contactor rated for 37 kW at 400 V in AC-2 duty — the standard for slip-ring motor starting and reversing. If your line uses jogging or reversing on conveyors or hoists, the AC-4 figure is the one that decides contact life. Coil is 24 V DC, pulling 0.8 A on pickup. That's a standard PLC-level control voltage — no separate power supply needed if your cabinet already runs 24 VDC. ## Panel Fit and Clearance Footprint is 70 mm wide by 146 mm tall by 201 mm deep. That depth is the one that catches panel builders — it's deeper than a typical S2 contactor, so verify gland-plate clearance and door swing before laying out the backplane. Side-by-side mounting is allowed, which helps when you're stacking multiple contactors on a motor control center bus. Terminals are screw-type on the main circuit, accepting 2x (10–50 mm²) stranded or 2x (0.25–2.5 mm²) solid. The auxiliary circuit handles 2x (2.5–16 mm²) solid/stranded. If your panel sits near a furnace line or in an unheated warehouse, the -25 °C floor is fine for most plants; the +60 °C ceiling handles interior cabinet heat rise without forced ventilation. ## Switching Cycles and Contact Life Mechanical life is a typical 10 million operations — that's the contactor frame, not the contacts. Electrical life depends on duty: at AC-3 (standard squirrel-cage motor start/run) you get up to 1,000 cycles per hour; at AC-4 (inching/jogging) it drops to 300 cycles per hour. This is a quoted-to-order item through distribution. The SIRIUS series is widely stocked, but the -3MA0 variant may not sit on every distributor's shelf. Send an RFQ with your quantity and target delivery window.","metaTitle":"Siemens 3RT1045-3BB44-3MA0 SIRIUS Power Contactor, S3, 37 kW","metaDescription":"Siemens 3RT1045-3BB44-3MA0 SIRIUS power contactor, size S3. 37 kW at 400 V AC-2, 66 A AC-4. Screw terminals, 24 VDC coil. Active production, sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"201 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"70 mm","at DC":"14 ... 20 ms","Height":"146 mm","Stranded":"2x (10 ... 50 mm²)","Arcing Time":"10 ... 15 ms","Rated Value":"24 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":"spring-loaded 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 (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","reference code according to IEC 81346-2":"Q","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)","Thermal Short-Time Current Limited To 10 S":"760 A","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","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=112088&mlfb=3RT1045-3BB44-3MA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1045-3BB44-3MA0/alternatives.json"},"ai":{"faq":[{"question":"What compliance documentation does this contactor carry?","answer":"RoHS compliance is confirmed with a substance prohibition date of May 1, 2012. The IP20 front / IP00 terminal rating indicates basic ingress protection. For UL/CSA or other agency approvals, the evidence does not list specific certifications; request the manufacturer's declaration from your Siemens channel partner."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1045-3BB44-3MA0","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/3RT1045-3BB44-3MA0 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}}