{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT2037-1KB44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT2037-1KB44","canonicalUrl":"https://aoctrl.com/siemens/3RT2037-1KB44","factsUrl":"https://aoctrl.com/api/mcp/products/3RT2037-1KB44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS coupling contactor, 24 VDC coil, Size S2, screw-type terminals, 55 mm width, 114 mm height, 174 mm depth, screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715.","salesMarkdown":"The Siemens 3RT2037-1KB44 is a SIRIUS coupling contactor — a Size S2 unit with a 24 VDC coil, screw-type terminals, and a footprint of 55 mm wide by 114 mm tall by 174 mm deep. ## Coil and switching behaviour The coil is rated 24 VDC with a holding current draw of 6 A at rated voltage, and an inrush peak of 2.6 A. Dropout delay on DC is 30 to 55 ms, and arcing time runs 10 to 20 ms — useful to know when coordinating control logic timing or suppression networks. The coil connection uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire. ## Switching capacity and duty ratings This contactor carries main contacts rated 18 to 1 (likely a NO/NC configuration count per the SIRIUS convention). Switching frequency varies by duty class: up to 800 operations per hour at AC-1 (resistive), 700/h at AC-3 and AC-3e (motor starting/running), 400/h at AC-2 (slip-ring motor), and 200/h at AC-4 (plugging/inching). For DC switching, the ratings are voltage-dependent: 6 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, 3 A at 400 V, and 0.6 A at 440 V. At 230 V AC it is rated for 10 hp motor load.","metaTitle":"Siemens 3RT2037-1KB44 SIRIUS Coupling Contactor, 24 VDC, Siz","metaDescription":"Siemens 3RT2037-1KB44 SIRIUS coupling contactor, 24 VDC coil, Size S2. 55 mm wide, screw terminals, DIN rail mount. Current lifecycle stage. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"174 mm","Width":"55 mm","at DC":"30 ... 55 ms","Height":"114 mm","Upwards":"10 mm","Forwards":"10 mm","Downwards":"10 mm","Arcing Time":"10 ... 20 ms","At The Side":"6 mm","Rated Value":"24 V","Initial Value":"0.8","During Storage":"-55 ... +80 °C","Of Magnet Coil":"Screw-type terminals","at AC-1 maximum":"800 1/h","at AC-2 maximum":"400 1/h","at AC-3 maximum":"700 1/h","at AC-4 maximum":"200 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":"1.2","at AC-3e maximum":"700 1/h","For Main Contacts":"18 ... 1","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":"S2","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Inrush Current Peak":"2.6 A","Product Designation":"Coupling 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":"10 hp","at 400 V rated value":"3 A","at 440 V rated value":"0.6 A","at 480 V rated value":"65 A","at 500 V rated value":"2 A","at 600 V rated value":"52 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":"5 hp","at 200/208 V rated value":"20 hp","at 220/230 V rated value":"20 hp","at 460/480 V rated value":"50 hp","at 575/600 V rated value":"50 hp","Locked-Rotor Current Peak":"2.1 A","Relative Humidity Minimum":"10 %","Holding Current Mean Value":"40 mA","Of Main Circuit Rated Value":"6 kV","at AC-3 rated value maximum":"690 V","at AC in hot operating state":"11.4 W","at AC-2 at 400 V rated value":"30 kW","at AC-3e rated value maximum":"690 V","at AC-4 at 400 V rated value":"55 A","safety-related switching OFF":"Yes","Substance Prohibitance (Date)":"10/01/2014","Design Of The Surge Suppressor":"with varistor","Duration Of Inrush Current Peak":"50 µs","Locked-Rotor Current Mean Value":"0.9 A","Duration Of Locked-Rotor Current":"230 ms","Of Auxiliary Circuit Rated Value":"6 kV","at AC-5a up to 690 V rated value":"70.4 A","at AC-5b up to 400 V rated value":"53.9 A","For Auxiliary And Control Circuit":"screw-type terminals","Function Module For Communication":"No","With Type Of Assignment 2 Required":"gG: 125A (690V,100kA), aM: 63A (690V,100kA), BS88: 100A (415V,80kA)","Without Load Current Share Typical":"1 W","closing power of magnet coil at DC":"21.5 W","holding power of magnet coil at DC":"1 W","At Contactor For Auxiliary Contacts":"Screw-type terminals","With Type Of Coordination 1 Required":"gG: 250 A (690 V, 100 kA), aM: 160 A (690 V, 100 kA), BS88: 200 A (415 V, 80 kA)","at AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","operational current at AC-12 maximum":"10 A","at AC in hot operating state per pole":"3.8 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), 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":"1 055 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 5 S Switching At Zero Current Maximum":"730 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 10 S Switching At Zero Current Maximum":"520 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 30 S Switching At Zero Current Maximum":"336 A; Use minimum cross-section acc. to AC-1 rated value","Limited To 60 S Switching At Zero Current Maximum":"272 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":"25 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":"$177.80","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=578163&mlfb=3RT2037-1KB44","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT2037-1KB44/alternatives.json"},"ai":{"faq":[{"question":"What are the key dimensions of 3RT2037-1KB44?","answer":"Width is 55 mm, height is 114 mm, and depth is 174 mm. It mounts on 35 mm DIN rail per DIN EN 60715."},{"question":"What is the coil voltage and holding current for 3RT2037-1KB44?","answer":"The coil is rated 24 VDC with a holding current of 6 A at rated voltage and an inrush peak of 2.6 A."},{"question":"Will 3RT2037-1KB44 drop into a panel specified around 3RT2036-1AC20-ZX95?","answer":"Both are SIRIUS Size S2 contactors on the same DIN-rail footprint, so the panel cutout and mounting rail are compatible. Verify the coil voltage and auxiliary contact configuration — the 3RT2037-1KB44 has a 24 VDC coil and no auxiliary switch, while the 3RT2036 variant may differ. Check your BOM for those details before swapping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT2037-1KB44","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/3RT2037-1KB44 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}}