{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2122-4KB40-0LA0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2122-4KB40-0LA0","canonicalUrl":"https://aoctrl.com/siemens/3RH2122-4KB40-0LA0","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2122-4KB40-0LA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary contactor, size S00, 24 VDC coil with integrated suppressor diode, 2 NO instantaneous contacts, screw and snap-on mounting on 35 mm DIN rail, 117 mm depth, 45 mm width.","salesMarkdown":"The S00 frame is 45 mm wide, 57.5 mm tall, and 117 mm deep, so it fits the standard S00 footprint that shares the same rail spacing as the 3RT2 contactors. The 2 NO contacts are rated for AC switching at 10 000 operations per hour, with an arcing time of 10 to 15 ms. DC switching is specified at 7 to 20 ms. The contacts handle a range of voltages: 10 A at 24 V AC, 10 A at 230 V AC, 3 A at 400 V AC, and 1 A at 690 V AC. For DC loads, the ratings drop — 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. That's typical for a S00 auxiliary contactor; the DC derating is steep because DC arcs don't self-extinguish at zero-crossing. ## Coil and environmental specs The 24 VDC coil draws 13 W on pickup and 4 W holding — the holding power is low enough that a standard 24 VDC power supply can keep it energized continuously without overheating. Operating temperature range is -40 to +70 °C, storage is -55 to +80 °C, with relative humidity minimum 10 %.","metaTitle":"Siemens 3RH2122-4KB40-0LA0 SIRIUS Auxiliary Contactor, 24 VD","metaDescription":"Siemens SIRIUS 3RH2122-4KB40-0LA0 auxiliary contactor, size S00, 24 VDC coil, 2 NO contacts, 10 A rated. Screw and snap-on DIN rail mount. Active production, sourced to order. Requ","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"117 mm","Width":"45 mm","at AC":"10 000 1/h","at DC":"7 ... 20 ms","title":"3RH2122-4KB40-0LA0","Height":"57.5 mm","Upwards":"10 mm","Forwards":"10 mm","Downwards":"10 mm","Arcing Time":"10 ... 15 ms","At The Side":"6 mm","Rated Value":"24 V","description":"Contactor relay for railway, 2 NO + 1 NC, 24 V DC, 0.7... 1.25* US, with integrated suppressor diode, Size S00, ring cable lug connection suitable for PLC outputs","Initial Value":"0.7","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-40 ... +70 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail","Full-Scale Value":"1.25","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":"S00","Product Brand Name":"SIRIUS","Degree Of Pollution":"3","Product Designation":"Auxiliary contactor","at 24 V rated value":"10 A","at 60 V rated value":"4.7 A","Of Contactor Typical":"30 000 000","at 110 V rated value":"3 A","at 220 V rated value":"1.2 A","at 230 V rated value":"10 A","at 400 V rated value":"3 A","at 440 V rated value":"0.5 A","at 500 V rated value":"2 A","at 600 V rated value":"0.26 A","at 690 V rated value":"1 A","Instantaneous Contact":"2","Relative Humidity Minimum":"10 %","Substance Prohibitance (Date)":"10/01/2009","Design Of The Surge Suppressor":"suppressor diode","Product Extension Auxiliary Switch":"Yes","closing power of magnet coil at DC":"13 W","holding power of magnet coil at DC":"4 W","Surge Voltage Resistance Rated Value":"6 kV","operating frequency at DC-12 maximum":"1 000 1/h","operating frequency at DC-13 maximum":"1 000 1/h","operational current at AC-12 maximum":"10 A","reference code according to IEC 81346-2":"K","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","with low demand rate according to SN 31920":"40 %","with high demand rate according to SN 31920":"73 %","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"2","Type Of Voltage Of The Control Supply Voltage":"DC","contact rating of auxiliary contacts according to UL":"A600 / Q600","Identification Number And Letter For Switching Elements":"21","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Of The Contactor With Added Auxiliary Switch Block Typical":"10 000 000","Type Of Electrical Connection For Auxiliary And Control Circuit":"ring terminal lug connection","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Of The Contactor With Added Electronically Optimized Auxiliary Switch Block Typical":"5 000 000","Design Of The Fuse Link For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A","design of the miniature circuit breaker for short-circuit protection of the auxiliary circuit up to 230 V":"C characteristic: 6 A; 0.4 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/12eb9814e64186349134e70c2f23771b.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=431437&mlfb=3RH2122-4KB40-0LA0"},"ai":{"faq":[{"question":"Where can I buy 3RH2122-4KB40-0LA0 and get a price?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."},{"question":"Will 3RH2122-4KB40-0LA0 drop into a panel specified around 3RH2122-1BA40 without rewiring?","answer":"Both are S00 frame auxiliary contactors with the same DIN rail footprint and 45 mm width, so the mechanical fit is identical. The difference is the coil voltage — 3RH2122-4KB40-0LA0 has a 24 VDC coil with an integrated suppressor diode, while the 1BA40 variant uses a different coil voltage. If the panel was wired for a 24 VDC coil, this part drops in without rewiring. Verify the coil voltage matches your control circuit before swapping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2122-4KB40-0LA0","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/3RH2122-4KB40-0LA0 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}}