{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1926-2FK21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1926-2FK21","canonicalUrl":"https://aoctrl.com/siemens/3RT1926-2FK21","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1926-2FK21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch, 3RT1926-2FK21, adjustable off-delay 0.5-10 s, 100-127 V 50/60 Hz coil, 3 A rated, clip-on DIN rail mount.","salesMarkdown":"## Off-delay auxiliary switch for SIRIUS contactors The 3RT1926-2FK21: It clips onto the front of any SIRIUS 3RT1 contactor (sizes S00 through S3) and draws its operating power from the contactor coil terminals, so no separate control voltage is needed. ## Switching ratings and contact load The switch contacts are rated 3 A maximum — this is the total switching capacity, not per-pole. At 24 V DC the rating drops to 1 A, at 125 V AC it is 0.2 A, and at 250 V AC it is 0.1 A. Those derated figures matter when the auxiliary switch feeds a PLC input or a small relay coil: a 24 V DC solenoid pulling 0.5 A is fine; a 250 V AC pilot light drawing 80 mA is within the 0.1 A limit. The block clips onto the contactor without tools — no extra DIN-rail space needed, since it rides on the contactor face. Mounting position is any orientation. The insulation class is basic, pollution degree 3, so it is suited for standard industrial control panels without special sealing. Dimensions are 33 mm wide, 46 mm high, 73 mm deep — the depth is the overhang past the contactor face, which matters when the panel door clearance is tight.","metaTitle":"Siemens 3RT1926-2FK21 SIRIUS Auxiliary Switch","metaDescription":"Siemens 3RT1926-2FK21 SIRIUS auxiliary switch with adjustable off-delay 0.5-10 s, 100-127 V 50/60 Hz coil, 3 A rated, clip-on DIN rail. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"73 mm","Solid":"18 ... 14","Width":"33 mm","title":"3RT1926-2FK21","Height":"46 mm","Maximum":"3 A","Upwards":"0 m","at 24 V":"1 A","Forwards":"0 m","ON-delay":"No","Stranded":"18 ... 14","at 125 V":"0.2 A","at 250 V":"0.1 A","at 50 Hz":"100 ... 127 V","at 60 Hz":"100 ... 127 V","Backwards":"0 m","Downwards":"0 m","OFF delay":"No","At The Side":"0 m","description":"solid-state time-delayed front-side auxiliary switch Time range 0.5...10 s, 100... 127 V AC / DC, 1 NO contact, 1 NC contact OFF delay, without control signal for 3RT1","Non-Volatile":"No","Initial Value":"0.85","Pulse Delayed":"No","Pulse-Shaping":"No","Recovery Time":"150 ms","During Storage":"-40 ... +85 °C","Adjustable Time":"0.5 ... 10 s","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","During Transport":"-40 ... +85 °C","Fastening Method":"clip-on","Full-Scale Value":"1.1","Delayed Switching":"0","Mounting Position":"any","additive ON-delay":"No","minimum ON period":"200 ms","ON-delay/OFF-delay":"No","Product Brand Name":"SIRIUS","Star-Delta Circuit":"No","Type Of Insulation":"Basic insulation","Degree Of Pollution":"3","Product Designation":"auxiliary switch","Passing Make Contact":"No","for AWG cables solid":"2x (20 ... 14)","Design Of The Product":"With OFF-delay","Instantaneous Contact":"0","Passing Break Contact":"No","OFF delay/instantaneous":"No","for AWG cables stranded":"2x (20 ... 14)","Relative Repeat Accuracy":"1 %","Pulse Delayed/Instantaneous":"No","Pulse-Shaping/Instantaneous":"No","Substance Prohibitance (Date)":"07/01/2006","ON-delay/instantaneous contact":"No","additive ON-delay/instantaneous":"No","ON-delay/OFF-delay/instantaneous":"No","Variably Clocked With Pulse Start":"No","Control Supply Voltage Frequency 1":"50 ... 60 Hz","Relative Humidity During Operation":"15 ... 95 %","Star-Delta Circuit With Delay Time":"No","Passing Break Contact/Instantaneous":"No","Product Function Star-Delta Circuit":"No","Surge Voltage Resistance Rated Value":"4 000 V","Variably Clocked With Interval Start":"No","Constant Clock Cycle With Pulse Start":"No","EMC immunity according to IEC 61812-1":"EN 61000-6-2","Flashing Symmetrically With Pulse Start":"No","Product Component Semi-Conductor Output":"No","due to burst according to IEC 61000-4-4":"2 kV network connection / 1 kV control connection","reference code according to IEC 81346-2":"K","Constant Clock Cycle With Interval Start":"No","Finely Stranded With Core End Processing":"0.5 ... 2.5 m²","Flashing Asymmetrically With Pulse Start":"No","Product Extension Optional Remote Control":"No","Product Extension Required Remote Control":"No","Flashing Symmetrically With Interval Start":"No","Passing Make Contact/Instantaneous Contact":"No","Design Of The Control Terminal Non-Floating":"No","Flashing Asymmetrically With Interval Start":"No","shock resistance according to IEC 60068-2-27":"11g / 15 ms","Retriggerable With Deactivated Control Signal":"No","Type Of Voltage Of The Control Supply Voltage":"AC","vibration resistance according to IEC 60068-2-6":"10 ... 55 Hz: 0.35 mm","Retrotriggerable With Switched-On Control Signal":"No","Mechanical Service Life (Operating Cycles) Typical":"10 000 000","Size Of Contactor Can Be Combined Company-Specific":"S0 ... S12","electrostatic discharge according to IEC 61000-4-2":"4 kV contact discharge / 8 kV air discharge","At The Relay Outputs Switchover Delayed/Without Delay":"No","Flashing Symmetrically With Pulse Start/Instantaneous":"No","Relative Setting Accuracy Relating To Full-Scale Value":"15 %","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Flashing Symmetrically With Interval Start/Instantaneous":"No","Type Of Electrical Connection For Auxiliary And Control Circuit":"screw-type terminals","Product Component Removable Terminal For Auxiliary And Control Circuit":"No","Retrotriggerable With Deactivated Control Signal/Instantaneous Contact":"No","Retrotriggerable With Switched-On Control Signal/Instantaneous Contact":"No","Design Of The Fuse Link For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 4 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$39.37","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/635cfa91e9c03682606d8f80bfddc7f4.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=34189&mlfb=3RT1926-2FK21"},"ai":{"faq":[{"question":"What is the off delay time range of Siemens 3RT1926-2FK21?","answer":"The off-delay is adjustable from 0.5 to 10 seconds, set by a potentiometer on the side of the auxiliary switch block."},{"question":"Is Siemens 3RT1926-2FK21 compatible with all Siemens 3RT1 contactors?","answer":"Yes, the 3RT1926-2FK21 clips onto the front of any SIRIUS 3RT1 contactor in sizes S00 through S3. It draws its operating power from the contactor coil terminals."},{"question":"What is the difference between 3RT1926-2FK21 and 3RT1926-2FK20?","answer":"The 3RT1926-2FK20 is the on-delay version; the 3RT1926-2FK21 is the off-delay version. Both have the same 0.5-10 s adjustable time range and the same coil voltage ratings."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1926-2FK21","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/3RT1926-2FK21 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}