{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB3143-4UB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB3143-4UB0","canonicalUrl":"https://aoctrl.com/siemens/3RB3143-4UB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB3143-4UB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS solid-state overload relay, 3RB3143-4UB0, Size S3, 50 A thermal current, adjustable trip classes 5E/10E/20E/30E, contactor mounting.","salesMarkdown":"The Siemens 3RB3143-4UB0 is a SIRIUS solid-state overload relay — Size S3, rated for a thermal current of 50 A, designed to protect motors against overload and phase failure. It mounts directly onto a contactor, saving DIN-rail space in the panel. Trip class is field-adjustable among CLASS 5E, 10E, 20E, and 30E, so you match the relay's response to the motor's starting characteristics — fast for low-inertia loads, slower for high-inertia starts like fans or conveyors. The note 'for message tripped' means the signaling contact 97/98 changes state when the relay has tripped, giving a discrete output to a PLC or indicator lamp. That contact is rated 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V — enough for most control circuits without an interposing relay. Thermal current of 50 A at both 480 V and 600 V means this relay handles the full motor FLA up to that level in a 480Y/277 or 600V delta system — common for North American industrial feeds. The maximum operating voltage is 1 000 V, covering 690 V IEC applications as well. Storage and transport range is -40 to +80 °C. Vibration resistance of 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles, plus shock resistance of 8g / 11 ms, qualifies it for mounting on machinery that sees regular vibration — pumps, compressors, conveyor drives. Fastening method is contactor mounting — it clips directly onto the matching SIRIUS contactor, no DIN rail needed. Main circuit terminals accept 1x (0.5 to 4 mm²) solid or 2x (0.5 to 2.5 mm²) stranded, with screw-type terminals requiring a Pozidriv PZ2 tip and 5-6 mm shaft diameter. For larger conductors, stranded up to 2x 16 mm² is accepted. Dimensions are 70 mm wide, 106 mm high, 124 mm deep — Size S3 frame. That's a compact footprint for a 50 A solid-state relay; verify clearance for the depth behind the panel door. For a BOM freeze or long-term planning, this relay has no known PCN or LTB. The SIRIUS platform is Siemens' mainstream motor-protection line, so cross-generational compatibility is stable.","metaTitle":"Siemens 3RB3143-4UB0 SIRIUS Solid-State Overload Relay, 50 A","metaDescription":"Siemens 3RB3143-4UB0 SIRIUS solid-state overload relay, 50 A thermal current, adjustable trip classes 5E-30E, contactor mounting, active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"tripped\"","Depth":"124 mm","Solid":"1x (0.5 ... 4 mm²), 2x (0.5 ... 2.5 mm²)","Width":"70 mm","title":"3RB3143-4UB0","Height":"106 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":"0.3 W","Stranded":"2x 16 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":"1 000 V","description":"Overload relay 12.5...50 A Electronic For motor protection Size S3, Class 5E...30E Contactor mounting Main circuit: Screw Auxiliary circuit: Screw Manual-Automatic-Reset","During Storage":"-40 ... +80 °C","Thermal Current":"50 A","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","During Transport":"-40 ... +80 °C","Fastening Method":"Contactor mounting","Shock Resistance":"8g / 11 ms","For Main Contacts":"M6","Mounting Position":"any","Solid Or Stranded":"1x (0,5 ... 4 mm²), 2x (0,5 ... 2,5 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":"50 A","at 600 V rated value":"50 A","Size Of Overload Relay":"S3","For Main Current Circuit":"screw-type 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\": 8g / 11 ms","at AC-3e rated value maximum":"1 000 V","Substance Prohibitance (Date)":"03/01/2017","Design Of The Auxiliary Switch":"integrated","Design Of The Overload Release":"electronic","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"50 A","for AC motors at 500 V at 50 Hz":"11 ... 30 kW","for AC motors at 690 V at 50 Hz":"11 ... 45 kW","for remote-reset function at DC":"24 V","For Auxiliary And Control Circuit":"screw-type terminals","Between Main And Auxiliary Circuit":"690 V","Relative Humidity During Operation":"10 ... 95 %","With Type Of Assignment 2 Required":"gG: 200 A","Display Version For Switching Status":"Slide switch","Surge Voltage Resistance Rated Value":"8 kV","With Type Of Coordination 1 Required":"gG: 200 A","for 3-phase motors at 400 V at 50 Hz":"7.5 ... 22 kW","Of The Auxiliary And Control Contacts":"M3","for AWG cables for auxiliary contacts":"2x (20 ... 14)","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":"1x (0.5 ... 2.5 mm²), 2x (0.5 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","For Main Contacts With Screw-Type Terminals":"4.5 ... 6 N·m","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","For Auxiliary Contacts With Screw-Type Terminals":"0.8 ... 1.2 N·m","operational current at AC-3e at 400 V rated value":"50 A","Size Of Contactor Can Be Combined Company-Specific":"S3","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":"1 000 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":"0.9 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"12.5 ... 50 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/e573d985c47da8f40ebc92f80d3039b6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=629746&mlfb=3RB3143-4UB0"},"ai":{"faq":[{"question":"What does the note 'for message tripped' mean?","answer":"It means the signaling contact (terminals 97/98) is dedicated to indicating a tripped state. When the relay trips from overload or phase loss, that contact changes state to send a signal to a PLC, light, or alarm."},{"question":"What are the key ratings I need to check for fit?","answer":"Thermal current is 50 A continuous at up to 600 V. Trip class is adjustable among 5E, 10E, 20E, and 30E. Operating temperature range is -25 to +60 °C. It mounts directly onto a SIRIUS contactor."},{"question":"What is the physical size of this overload relay?","answer":"It's a Size S3 frame: 70 mm wide, 106 mm high, 124 mm deep. That's the envelope for panel layout — allow depth clearance behind the door for wiring."},{"question":"Can this relay be used on a machine that vibrates?","answer":"Yes, it's rated for vibration of 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles, plus shock of 8g / 11 ms. Suitable for pumps, compressors, and conveyor drives mounted on machinery."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB3143-4UB0","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/3RB3143-4UB0 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}}