{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1916-2FK21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1916-2FK21","canonicalUrl":"https://aoctrl.com/siemens/3RT1916-2FK21","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1916-2FK21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch, 3RT1916-2FK21, rated 3 A maximum, adjustable time 0.5-10 s, clip-on mounting, 45 mm width, 75 mm depth.","salesMarkdown":"Rated 3 A maximum, it carries a 1 A switching capacity at 24 V and 0.1 A at 250 V. The adjustable time range of 0.5 to 10 s covers common delay-on applications like staggered motor starts or sequence interlocks. The 3 A maximum rating governs the auxiliary contact's thermal continuous current — it's sized for signal-level switching (PLC inputs, relay coils), not motor power. The 0.1 A at 250 V AC rating reflects the break capacity under inductive load; expect derating for DC circuits. The adjustable time range of 0.5 to 10 s is set via a potentiometer on the face, with a recovery time of 150 ms between cycles — enough for most conveyor or pump sequencing, but too slow for fast-cycling applications like stamping presses where a minimum ON period of 200 ms applies. The clip-on fastening method means it snaps directly onto the front of a SIRIUS 3RT2 contactor or 3RA2 starter without tools. Width is 45 mm, depth 75 mm, height 38 mm — it adds one module width to the assembly. ## Environmental and insulation specs The 0 m altitude rating for all axes (upwards, forwards, backwards, downwards, at the side) indicates the part is rated for standard atmospheric pressure only — no high-altitude derating is published.","metaTitle":"Siemens 3RT1916-2FK21 SIRIUS Auxiliary Switch, 3 A, 0.5-10 s","metaDescription":"Siemens 3RT1916-2FK21 SIRIUS auxiliary switch, rated 3 A max, adjustable time 0.5-10 s, clip-on mount, 45 mm width. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"75 mm","Solid":"18 ... 14","Width":"45 mm","Height":"38 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","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","at AWG cables solid":"2x (20 ... 14)","Passing Make Contact":"No","Instantaneous Contact":"0","Passing Break Contact":"No","at AWG cables stranded":"2x (20 ... 14)","OFF delay/instantaneous":"No","Relative Repeat Accuracy":"1 %","Pulse Delayed/Instantaneous":"No","Pulse-Shaping/Instantaneous":"No","Substance Prohibitance (Date)":"01.07.2006 00:00:00","Design Of The Surge Suppressor":"with varistor","ON-delay/instantaneous contact":"No","additive ON-delay/instantaneous":"No","EMC immunity acc. to IEC 61812-1":"EN 61000-6-2","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","due to burst acc. to IEC 61000-4-4":"2 kV network connection / 1 kV control connection","reference code acc. to IEC 81346-2":"K","Passing Break Contact/Instantaneous":"No","Product Function Star-Delta Circuit":"No","protection class IP of the terminal":"IP20","Surge Voltage Resistance Rated Value":"4 000 V","Variably Clocked With Interval Start":"No","Constant Clock Cycle With Pulse Start":"No","Flashing Symmetrically With Pulse Start":"No","Product Component Semi-Conductor Output":"No","shock resistance acc. to IEC 60068-2-27":"11g / 15 ms","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","vibration resistance acc. to IEC 60068-2-6":"10 ... 55 Hz: 0.35 mm","Design Of The Control Terminal Non-Floating":"No","Flashing Asymmetrically With Interval Start":"No","Retriggerable With Deactivated Control Signal":"No","Type Of Voltage Of The Control Supply Voltage":"AC","electrostatic discharge acc. to IEC 61000-4-2":"4 kV contact discharge / 8 kV air discharge","field-based interference acc. to IEC 61000-4-3":"10 V/m","Retrotriggerable With Switched-On Control Signal":"No","Mechanical Service Life (Operating Cycles) Typical":"10 000 000","Size Of Contactor Can Be Combined Company-Specific":"S00","due to conductor-earth surge acc. to IEC 61000-4-5":"2 kV","protection class IP on the front acc. to IEC 60529":"IP20","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 Function 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":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=305960&mlfb=3RT1916-2FK21","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1916-2FK21/alternatives.json"},"ai":{"faq":[{"question":"What is the adjustable time range on 3RT1916-2FK21?","answer":"The adjustable time range is 0.5 to 10 s, set via a potentiometer. The recovery time between cycles is 150 ms, and the minimum ON period is 200 ms."},{"question":"Where can I buy 3RT1916-2FK21?","answer":"This part is sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for your quantity and delivery window."},{"question":"What wire sizes does 3RT1916-2FK21 accept?","answer":"The terminals accept solid and stranded wire from 18 to 14 AWG."},{"question":"What is the switching capacity at different voltages?","answer":"At 24 V the rated capacity is 1 A; at 125 V it is 0.2 A; at 250 V it is 0.1 A. The maximum continuous current is 3 A."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1916-2FK21","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/3RT1916-2FK21 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}}