{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2028-2BB44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2028-2BB44","canonicalUrl":"https://aoctrl.com/siemens/3RT2028-2BB44","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2028-2BB44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT2028-2BB44 power contactor, Size S0, 24 VDC coil, spring-type terminals, 45 mm width, 102 mm height, 154 mm depth.","salesMarkdown":"The 45 mm width and 102 mm height leave room for adjacent devices in a crowded rail. The main contacts are rated for 18 to 8 A, but the real selection driver is the duty-specific switching frequency. At AC-3 (squirrel-cage motor starting), the contactor handles up to 750 operations per hour; at AC-4 (plugging/reversing), that drops to 250 ops/h. For resistive loads (AC-1), it can cycle at 1,000 ops/h. These limits govern thermal rise in the enclosure — pushing past them accelerates contact wear. The 24 VDC coil draws 6 A at rated value, with a dropout time of 15 to 18 ms. Switching capacity on the coil side is specified across voltages: 2 A at 48 VDC, 1 A at 110 VDC, 0.3 A at 220 VDC, and 3 A at 400 VAC. The 1.1 full-scale factor and 0.8 initial value bracket the coil's operating range under varying supply conditions. Spring-type terminals accept solid or stranded wire from 1 to 10 mm², with dual-wire capability for 2x (0.5 to 2.5 mm²). This eliminates the need for ferrules on stranded conductors and speeds panel wiring.","metaTitle":"Siemens 3RT2028-2BB44 SIRIUS Power Contactor, Size S0, 24 VD","metaDescription":"Siemens 3RT2028-2BB44 SIRIUS power contactor, Size S0, 24 VDC coil, spring-type terminals. Rated for AC-3 motor switching at 750 ops/h. Current lifecycle stage. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"154 mm","Solid":"1 ... 10 mm²","Width":"45 mm","at DC":"15 ... 18 ms","Height":"102 mm","Upwards":"10 mm","Forwards":"10 mm","Stranded":"1 ... 10 mm²","Downwards":"10 mm","Arcing Time":"10 ... 10 ms","At The Side":"6 mm","Rated Value":"24 V","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Spring-type terminals","at AC-1 maximum":"1 000 1/h","at AC-2 maximum":"750 1/h","at AC-3 maximum":"750 1/h","at AC-4 maximum":"250 1/h","lifecycle_stage":"current","Auxiliary Switch":"No","During Operation":"-25 ... +60 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715","Full-Scale Value":"1.1","at AC-3e maximum":"750 1/h","For Main Contacts":"18 ... 8","Mounting Position":"+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface","Size Of Contactor":"S0","Solid Or Stranded":"2x (0.5 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Power contactor","at 24 V rated value":"6 A","at 48 V rated value":"2 A","at 60 V rated value":"2 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 125 V rated value":"0.9 A","at 220 V rated value":"0.3 A","at 230 V rated value":"5 hp","at 400 V rated value":"3 A","at 440 V rated value":"0.6 A","at 480 V rated value":"34 A","at 500 V rated value":"2 A","at 600 V rated value":"27 A","at 690 V rated value":"1 A","Side-By-Side Mounting":"Yes","For Auxiliary Contacts":"20 ... 14","For Main Current Circuit":"spring-loaded terminals","at 110/120 V rated value":"3 hp","at 200/208 V rated value":"10 hp","at 220/230 V rated value":"10 hp","at 460/480 V rated value":"25 hp","at 575/600 V rated value":"25 hp","Relative Humidity Minimum":"10 %","Of Main Circuit Rated Value":"6 kV","at AC-3 rated value maximum":"690 V","at AC in hot operating state":"9.6 W","at AC-2 at 400 V rated value":"18.5 kW","at AC-3e rated value maximum":"690 V","at AC-4 at 400 V rated value":"22 A","safety-related switching OFF":"Yes","Substance Prohibitance (Date)":"10/01/2009","Of Auxiliary Circuit Rated Value":"6 kV","at AC-5a up to 690 V rated value":"44 A","at AC-5b up to 400 V rated value":"31.5 A","For Auxiliary And Control Circuit":"spring-loaded terminals","Function Module For Communication":"No","With Type Of Assignment 2 Required":"gG: 50A (690V,100kA), aM: 25A (690V, 100kA), BS88: 50A (415V, 80kA)","Without Load Current Share Typical":"5.9 W","closing power of magnet coil at DC":"5.9 W","holding power of magnet coil at DC":"5.9 W","At Contactor For Auxiliary Contacts":"Spring-type terminals","With Type Of Coordination 1 Required":"gG: 125A (690V,100kA), aM: 50A (690V,100kA), BS88: 125A (415V,80kA)","at AWG cables for auxiliary contacts":"2x (20 ... 14)","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"3.2 W","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)","Number Of Poles For Main Current Circuit":"3","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes","with low demand rate according to SN 31920":"40 %","Finely Stranded Without Core End Processing":"2x (0.5 ... 2.5 mm²)","with high demand rate according to SN 31920":"73 %","Type Of Voltage Of The Control Supply Voltage":"DC","Limited To 1 S Switching At Zero Current Maximum":"593 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 5 S Switching At Zero Current Maximum":"341 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 10 S Switching At Zero Current Maximum":"260 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 30 S Switching At Zero Current Maximum":"199 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 60 S Switching At Zero Current Maximum":"162 A; Use minimum cross-section acc. to AC-1 rated value","contact rating of auxiliary contacts according to UL":"A600 / Q600","Of Main Circuit With Degree Of Pollution 3 Rated Value":"690 V","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","Of Auxiliary Circuit With Degree Of Pollution 3 Rated Value":"690 V","For Short-Circuit Protection Of The Auxiliary Switch Required":"gG: 10 A (500 V, 1 kA)","minimum cross-section in main circuit at maximum AC-1 rated value":"10 mm²","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":"$95.25","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=394844&mlfb=3RT2028-2BB44","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT2028-2BB44/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings for this contactor?","answer":"The 3RT2028-2BB44 is a Size S0 contactor with a 24 VDC coil, main contacts rated 18 to 8 A, AC-3 switching frequency of 750 ops/h, and spring-type terminals accepting 1 to 10 mm² wire."},{"question":"What clearance is needed around this contactor in a panel?","answer":"Minimum clearances are 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm at the side."},{"question":"What is the mechanical endurance of this contactor?","answer":"Typical mechanical endurance is 10 million operations."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2028-2BB44","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/3RT2028-2BB44 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}}