{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4075-6BB35","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4075-6BB35","canonicalUrl":"https://aoctrl.com/siemens/3RW4075-6BB35","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4075-6BB35","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4075-6BB35 soft starter, S12 frame, 356 A at 40 °C, 115 V AC control, 50/60 Hz, thyristor switched, screw fixing.","salesMarkdown":"## 356 A at 40 °C — the thermal ceiling that governs the BOM line The 3RW4075-6BB35: That 40 °C base is the derating temperature — above it the thyristor junction temperature rises faster than the heat sink can shed, so the continuous output current must be reduced per the manufacturer's curve. For a 300 A motor in a 45 °C panel, this part holds the unit on the grid with margin; for a 350 A motor at 50 °C, the 315 A ceiling means the starter will trip on overtemperature during a stalled-rotor start unless the ambient is brought down or a larger frame is selected. ## Mounting and panel integration — S12 frame, screw-fixed, clearance zones The S12 frame measures 160 mm wide by 230 mm tall by 278 mm deep, fastened to the backplate with screws — no DIN-rail snap-on. The mounting position is constrained by the fan: with the fan fitted, the unit can be rotated ±90° on a vertical surface and tilted ±22.5° front-to-back; without the fan, rotation is limited to ±10° and tilt to ±10°. These limits keep the thyristor heat sink within its designed convection path — exceeding them starves the cooling fins and derates the output below the published numbers. Clearance zones: 100 mm above the unit for cable bend radius and arc-flash standoff, 75 mm below for bottom-entry gland plates, and only 5 mm at the sides — tight side-by-side mounting is allowed, provided the top and bottom clearances are respected. The main power circuit accepts stranded cable 70 to 240 mm² or finely stranded 50 to 240 mm², with both front and back clamping points rated for 2/0 to 500 kcmil (North American sizes). For high-current feeds, busbar connection is also supported. ## Thyristor switching and protection — no mechanical contacts, integrated overload Switching is done by thyristors — semiconductor devices that turn on and off at the zero-crossing of the AC waveform, so there are no mechanical contacts to weld, pit, or arc. The minimum load is 20 % of the rated current; below that the motor current may not be sufficient to hold the thyristors in conduction, causing them to drop out and re-trigger on every half-cycle, which generates harmonics and heats the motor. For very light loads (pumps running dry, unloaded conveyors), a minimum-load resistor or a bypass contactor after start completion is standard practice. Motor overload protection is integrated — the soft starter measures motor current and trips on an I²t curve, so no separate overload relay is needed in the power circuit. Intrinsic device protection (thyristor over-temperature and over-current) is also built in, and an external reset input allows remote fault recovery from a DCS or PLC digital output. The adjustable current limitation lets the starting current be set between 20 % and 100 % of the motor full-load amps, which is the primary tool for tuning the start ramp to the load inertia. This is the standard industrial environment for motor control centres (MCCs) and panel shops; no additional conformal coating or sealed enclosure is required for normal factory-floor conditions.","metaTitle":"Siemens 3RW4075-6BB35 Soft Starter, SIRIUS, 356A at 40°C","metaDescription":"Siemens 3RW4075-6BB35 SIRIUS soft starter, 356 A at 40 °C, 115 V control, S12 frame. Active production. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"278mm","Solid":"2x (0.5 ... 2.5 mm²)","Width":"160mm","title":"3RW4075-6BB35","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S12 315 A, 300 hp/575 V, 50 °C 400-600 V AC, 115 V AC Screw terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5075-6AB15<<","During Storage":"-40 ... +80°C","External Reset":"Yes","Finely Stranded":"50 ... 240 mm²","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw fixing","Minimum Load [%]":"20%","For Main Contacts":"2/0 ... 500 kcmil","Mounting Position":"With additional fan: With vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back Without additional fan: With vertical mounting surface +/-10° rotatable, with vertical mounting surface +/- 10° t","Product Brand Name":"SIRIUS","Degree Of Pollution":"3, acc. to IEC 60947-4-2","Product Designation":"Soft starter","Wire Length Maximum":"300m","Derating Temperature":"40°C","Inside-Delta Circuit":"No","at 50 Hz rated value":"115V","at 60 Hz rated value":"115V","at 40 °C rated value":"356A","at 50 °C rated value":"315A","at 60 °C rated value":"280A","For Auxiliary Contacts":"2x (20 ... 14)","For Main Current Circuit":"busbar connection","Motor Overload Protection":"Yes","Using Both Clamping Points":"min. 2x 2/0, max. 2x 500 kcmil","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Size Of Engine Control Device":"S12","Using The Back Clamping Point":"250 ... 500 kcmil","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"3/0 ... 600 kcmil","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"red","Integrated Bypass Contact System":"Yes","during storage acc. to IEC 60721":"1K6 (only occasional condensation), 1C2 (no salt mist), 1S2 (sand must not get inside the devices), 1M4","For Auxiliary And Control Circuit":"screw-type terminals","during operation acc. to IEC 60721":"3K6 (no formation of ice, no condensation), 3C3 (no salt mist), 3S2 (sand must not get into the devices), 3M6","during transport acc. to IEC 60721":"2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m)","Product Component Motor Brake Output":"No","reference code acc. to DIN EN 61346-2":"Q","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Evaluation Of Thermistor Motor Protection":"No","at standard circuit at 40 °C rated value":"250kW","at standard circuit at 50 °C rated value":"300hp","Finely Stranded Without Core End Processing":"min. 2x 50 mm², max. 2x 185 mm²","number of CO contacts for auxiliary contacts":"1","number of NC contacts for auxiliary contacts":"0","number of NO contacts for auxiliary contacts":"2","Type Of Voltage Of The Control Supply Voltage":"AC","Control Supply Voltage Frequency 1 Rated Value":"50Hz","Control Supply Voltage Frequency 2 Rated Value":"60Hz","Installation Altitude At Height Above Sea Level":"5 000m","touch protection on the front acc. to IEC 60529":"finger-safe, for vertical contact from the front with cover","continuous operating current [% of Ie] at 40 °C":"115%","Operating Voltage At Standard Circuit Rated Value":"400 ... 600V","protection class IP on the front acc. to IEC 60529":"IP00; IP20 with cover","contact rating of auxiliary contacts according to UL":"B300 / R300","Relative Negative Tolerance Of The Operating Frequency":"-10%","Relative Positive Tolerance Of The Operating Frequency":"10%","For Auxiliary Contacts Finely Stranded With Core End Processing":"2x (20 ... 16)","Relative Negative Tolerance Of The Control Supply Voltage Frequency":"-10%","Relative Positive Tolerance Of The Control Supply Voltage Frequency":"10%","Relative Negative Tolerance Of The Operating Voltage At Standard Circuit":"-15%","Relative Positive Tolerance Of The Operating Voltage At Standard Circuit":"10%","power loss [W] at operational current at 40 °C during operation typical":"125W","relative negative tolerance of the control supply voltage at AC at 50 Hz":"-15%","relative negative tolerance of the control supply voltage at AC at 60 Hz":"-15%","relative positive tolerance of the control supply voltage at AC at 50 Hz":"10%","relative positive tolerance of the control supply voltage at AC at 60 Hz":"10%","Adjustable Motor Current For Motor Overload Protection Minimum Rated Value":"131A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$3,705.86","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/68863406fd3617d7348b11e9b8d6f287.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=389320&mlfb=3RW4075-6BB35"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 3RW4075-6BB35?","answer":"Pricing and stock are confirmed at quote time against an RFQ."},{"question":"What is 3RW4075-6BB35's rated current at different temperatures?","answer":"The derating temperature is 40 °C — above that the output current must be reduced per the manufacturer's curve to protect the thyristors."},{"question":"What compliance documentation does Siemens provide for 3RW4075-6BB35?","answer":"The part carries pollution degree 3 per IEC 60947-4-2 and is rated for 600 V insulation voltage. Specific RoHS, REACH, and UL documentation is available from Siemens upon request; the product is designed for IEC and UL installations."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4075-6BB35","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/3RW4075-6BB35 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}}