{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB3123-4SE0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB3123-4SE0","canonicalUrl":"https://aoctrl.com/siemens/3RB3123-4SE0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB3123-4SE0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RB3123-4SE0 solid-state overload relay, S0 size, 12 A thermal current, 690 V rated voltage, adjustable trip class 5E-30E, contactor mounting, spring-loaded terminals.","salesMarkdown":"It mounts directly onto a contactor — no DIN-rail bracket needed — and uses spring-loaded terminals for the main circuit, which saves time during panel wiring. The adjustable trip class (5E, 10E, 20E, or 30E) lets you match the relay's response to the motor's starting characteristics: a pump with a long acceleration ramp gets class 30E; a fast-cycling conveyor motor gets class 5E. The 12 A thermal current (Ith) is the continuous current the relay's main path can carry without exceeding temperature rise limits. For motor protection, the trip threshold is set by the current setting range: the relay trips when the motor current exceeds the upper setting value by a factor of 3.5 and resets when it drops below the lower setting value. The adjustable trip class gives you control over how long the relay waits before tripping on a locked-rotor condition — class 10E is the standard for most induction motors, while class 20E or 30E accommodates high-inertia loads that take longer to start. ## Signaling and Auxiliary Contact Ratings The integrated signaling contact (the note for message \"tripped\") provides a dry contact output that changes state when the relay trips. It's rated for 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, among other voltages — enough to drive a PLC input, an alarm lamp, or a remote annunciator directly. The contact's shock resistance is 15g / 11 ms (9g / 11 ms in the tripped position), so it holds its state through moderate panel vibration without false signals. Storage and transport limits extend from -40 to +80 °C. Vibration resistance covers 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles — typical for industrial machinery. Mounting position is unrestricted, so you can orient it vertically, horizontally, or upside-down on the contactor.","metaTitle":"Siemens 3RB3123-4SE0 SIRIUS Solid-State Overload Relay, 12 A","metaDescription":"Siemens 3RB3123-4SE0 SIRIUS solid-state overload relay, S0 size, 12 A thermal current, 690 V rated voltage, adjustable trip class 5E-30E, contactor mounting, spring-loaded terminal","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"tripped\"","Depth":"85 mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"45 mm","title":"3RB3123-4SE0","Height":"109 mm","Maximum":"IMotor < upper current setting value x 3.5","Minimum":"IMotor > lower current setting value","at 24 V":"2 A","at 60 V":"0.55 A","Per Pole":"0.2 W","Stranded":"1x 10 mm²","at 110 V":"0.3 A","at 120 V":"4 A","at 125 V":"0.3 A","at 220 V":"0.11 A","at 230 V":"3 A","Trip Class":"CLASS 5E, 10E, 20E and 30E adjustable","Rated Value":"690 V","description":"Overload relay 3...12 A Electronic For motor protection Size S0, Class 5...30 Contactor mounting Main circuit: Spring-type terminal Auxiliary circuit: Spring-type terminal Manual-Automatic-Reset Internal ground fault detection","During Storage":"-40 ... +80 °C","Thermal Current":"12 A","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","During Transport":"-40 ... +80 °C","Fastening Method":"Contactor mounting","Shock Resistance":"15g / 11 ms","For Main Contacts":"M4","Mounting Position":"any","Solid Or Stranded":"2x (0,25 ... 1,5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"solid-state overload relay","Vibration Resistance":"1-6 Hz, 15 mm; 6-500 Hz, 20 m/s²; 10 cycles","at 480 V rated value":"12 A","at 600 V rated value":"12 A","Size Of Overload Relay":"S0","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-25 ... +60 °C","Design Of Screwdriver Shaft":"Diameter 5 to 6 mm","Size Of The Screwdriver Tip":"Pozidriv PZ 2","according to IEC 60068-2-27":"15g / 11 ms; Signaling contact 97 / 98 in position \"Tripped\": 9g / 11 ms","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","Design Of The Auxiliary Switch":"integrated","Design Of The Overload Release":"electronic","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"12 A","for AC motors at 500 V at 50 Hz":"1.5 ... 5.5 kW","for AC motors at 690 V at 50 Hz":"2.2 ... 7.5 kW","for remote-reset function at DC":"24 V","For Auxiliary And Control Circuit":"spring-loaded terminals","Between Main And Auxiliary Circuit":"690 V","Relative Humidity During Operation":"10 ... 95 %","With Type Of Assignment 2 Required":"gG: 50 A, J: 45 A","Display Version For Switching Status":"Slide switch","Surge Voltage Resistance Rated Value":"6 kV","With Type Of Coordination 1 Required":"gG: 63 A, RK5: 45 A","for 3-phase motors at 400 V at 50 Hz":"1.5 ... 5.5 kW","for AWG cables for auxiliary contacts":"1x (24 ... 16), 2x (24 ... 16)","Between Auxiliary And Auxiliary Circuit":"300 V","due to burst according to IEC 61000-4-4":"2 kV (power ports), 1 kV (signal ports) corresponds to degree of severity 3","reference code according to IEC 81346-2":"F","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Finely Stranded Without Core End Processing":"2x (0.25 ... 1.5 mm²)","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","operational current at AC-3e at 400 V rated value":"12 A","Size Of Contactor Can Be Combined Company-Specific":"S0","electrostatic discharge according to IEC 61000-4-2":"6 kV contact discharge / 8 kV air discharge","Type Of Voltage Supply Via Input/Output Link Master":"No","contact rating of auxiliary contacts according to UL":"B600 / R300","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Response Time Of The Grounding Protection In Settled State":"1 000 ms","Response Value Current Of The Grounding Protection Minimum":"0.75 x IMotor","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gG: 6 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Product Component Removable Terminal For Auxiliary And Control Circuit":"Yes","power loss [W] for rated value of the current at AC in hot operating state":"0.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"3 ... 12 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ffee37f70d8b420ccd16c430224fb8be.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=62522&mlfb=3RB3123-4SE0"},"ai":{"faq":[{"question":"What does the note \"for message tripped\" mean?","answer":"That note refers to the signaling contact (terminals 97/98) which changes state when the overload relay trips. It provides a dry contact output rated for 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, among other voltages."},{"question":"What are the key ratings for this overload relay?","answer":"Thermal current (Ith) is 12 A, rated voltage is 690 V, and the trip class is adjustable to 5E, 10E, 20E, or 30E. The main circuit uses spring-loaded terminals, and the relay mounts directly onto a contactor."},{"question":"What is the depth of the 3RB3123-4SE0?","answer":"The depth is 85 mm. Width is 45 mm and height is 109 mm."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB3123-4SE0","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/3RB3123-4SE0 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}}