{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2028-1BM40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2028-1BM40","canonicalUrl":"https://aoctrl.com/siemens/3RT2028-1BM40","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2028-1BM40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT2028-1BM40 power contactor, S0 frame, 24 VDC coil, screw-type terminals, 45 mm width, 107 mm depth.","salesMarkdown":"It mounts on a 35 mm DIN rail per DIN EN 60715 via screw and snap-on fastening, fitting into a 45 mm wide slot with a 107 mm depth and 85 mm height. The DC switching ratings tell you exactly what this contactor can handle across common control voltages: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. These are the maximum currents the main contacts can interrupt at those DC voltage levels — critical for sizing the contactor to your load, especially in battery or rectified-supply circuits where DC arc extinction is harder than AC. For AC motor duty, the contactor is rated 5 hp at 230 V, which covers typical small pump, fan, or conveyor motors in that power class. The operating frequency limits per duty cycle are: 1,000 operations per hour at AC-1 (resistive), 750/h at AC-2 and AC-3 (motor starting/running), and 250/h at AC-4 (plugging/reversing). The AC-3e rating also sits at 750/h. These numbers govern how often the contactor can cycle without overheating — a panel-builder consideration for high-speed production lines. The contactor accepts solid or stranded conductors from 1 to 10 mm² on the main circuit, and fine-stranded wiring from 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) for auxiliary circuits. The coil dropout time on DC supply is 15 to 18 ms, and the arcing time is 10 ms. These timing specs matter for coordination with upstream protective devices and for sequencing in safety circuits where contactor dropout delay affects stop times.","metaTitle":"Siemens 3RT2028-1BM40 SIRIUS Power Contactor, S0 Frame, 24 V","metaDescription":"Siemens 3RT2028-1BM40 SIRIUS power contactor, S0 frame, 24 VDC coil, screw terminals. Rated 10 A at 24 VDC, 5 hp at 230 VAC. DIN rail mount. Current production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"107 mm","Solid":"1 ... 10 mm²","Width":"45 mm","at DC":"15 ... 18 ms","Height":"85 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":"220 V","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Screw-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":"Yes","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":"16 ... 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 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Power contactor","at 24 V rated value":"10 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":"screw-type 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-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":"screw-type 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":"Screw-type terminals","With Type Of Coordination 1 Required":"gG: 125A (690V,100kA), aM: 50A (690V,100kA), BS88: 125A (415V,80kA)","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"3.2 W","for AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","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)","mirror contact according to IEC 60947-4-1":"Yes","with low demand rate according to SN 31920":"40 %","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 / P600","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":"1","number of NO contacts for auxiliary contacts instantaneous contact":"1","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=45784&mlfb=3RT2028-1BM40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT2028-1BM40/alternatives.json"},"ai":{"faq":[{"question":"What are the key DC switching ratings for this contactor?","answer":"The main contacts are rated 10 A at 24 VDC, 2 A at 48 VDC and 60 VDC, 1 A at 110 VDC, 0.9 A at 125 VDC, 0.3 A at 220 VDC, and 3 A at 400 VDC. These are the maximum interrupt ratings at each voltage level."},{"question":"What is the physical size and mounting of the 3RT2028-1BM40?","answer":"It is 45 mm wide, 85 mm high, and 107 mm deep. It mounts on a 35 mm DIN rail per DIN EN 60715 using screw and snap-on fastening."},{"question":"What conductor sizes does this contactor accept?","answer":"Solid or stranded conductors from 1 to 10 mm² on the main circuit. For auxiliary circuits, it accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) fine-stranded wire."},{"question":"Does the 3RT2028-1BM40 include an auxiliary contact block?","answer":"Yes, the contactor is equipped with an auxiliary switch as standard."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2028-1BM40","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/3RT2028-1BM40 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}}