{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4075-2BB34","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4075-2BB34","canonicalUrl":"https://aoctrl.com/siemens/3RW4075-2BB34","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4075-2BB34","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4075-2BB34 soft starter, size S12, 356 A at 40 °C, 115 V coil 50/60 Hz, 3-phase, screw fixing, busbar connection.","salesMarkdown":"## Rated current and what it means for the motor The 3RW4075-2BB34: That 40 °C figure is the baseline — above that, the thyristor junction temperature climbs and the output must be backed off. For a 315 A motor in a 50 °C panel, this starter lands right at the limit; for a 280 A motor at 60 °C, it's maxed out. The derating temperature is 40 °C, so if your enclosure runs hot, size up. ## Mounting and connections — what fits in the panel This is a size S12 frame — 230 mm high, 160 mm wide, 278 mm deep — fastened by screw fixing. The main current circuit uses busbar connection, accepting 2/0 to 500 kcmil at the back clamping point and 3/0 to 600 kcmil at the front. Stranded cable from 70 to 240 mm² or finely stranded 50 to 240 mm² fits the power terminals. Solid control wiring is 2x (0.25 to 1.5 mm²). Mounting position allows vertical surface with ±10° rotation without an additional fan; with the optional fan, ±90° rotation and ±22.5° tilt front/back. ## Protection and control features Built-in motor overload protection and intrinsic device protection are standard. Adjustable current limitation lets you set the starting current below the motor's locked-rotor draw — useful for soft starting conveyors or pumps where mechanical shock is a concern. Minimum load is 20 % of the rated current, so it won't regulate properly on a lightly loaded motor. External reset is available for remote restart after a fault. Pollution degree 3 per IEC 60947-4-2 means it's rated for industrial environments with conductive dust or humidity. ## Coil voltage and operating conditions Insulation voltage rated 600 V. Maximum motor cable length is 300 m — beyond that, capacitive charging current can cause nuisance trips or reduce starting torque. Not configurable for inside-delta connection.","metaTitle":"Siemens 3RW4075-2BB34 SIRIUS Soft Starter, 356 A, 115 V coil","metaDescription":"Siemens 3RW4075-2BB34 SIRIUS soft starter, 356 A at 40 °C, 115 V coil, size S12. Active production, quoted to order. Request RFQ for volume pricing.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"278mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"160mm","title":"3RW4075-2BB34","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S12 315 A, 250 hp/460 V, 50 °C 200-460 V AC, 115 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5075-2AB14<<","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 (24 ... 16)","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","For Auxiliary And Control Circuit":"spring-loaded terminals","Product Component Motor Brake Output":"No","during storage according to IEC 60721":"1K6 (only occasional condensation), 1C2 (no salt mist), 1S2 (sand must not get inside the devices), 1M4","reference code according to EN 61346-2":"Q","during operation according 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 according to IEC 60721":"2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m)","Finely Stranded With Core End Processing":"2x (0.25 ... 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":"200kW","at standard circuit at 50 °C rated value":"250hp","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","continuous operating current [% of Ie] at 40 °C":"115%","Operating Voltage At Standard Circuit Rated Value":"200 ... 460V","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%","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":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/39809b836fddee67cf964853fa109110.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=329672&mlfb=3RW4075-2BB34"},"ai":{"faq":[{"question":"What is the rated current of 3RW4075-2BB34 at 40 °C?","answer":"356 A at 40 °C ambient. Derates to 315 A at 50 °C and 280 A at 60 °C."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4075-2BB34","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/3RW4075-2BB34 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}}