{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4447-2BC35","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4447-2BC35","canonicalUrl":"https://aoctrl.com/siemens/3RW4447-2BC35","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4447-2BC35","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4447-2BC35 soft starter, 748 A at 40 °C, 690 V insulation voltage, 50/60 Hz, screw fixing, IP20.","salesMarkdown":"## Active production and thermal derating The 3RW4447-2BC35: Current rating is temperature-dependent: 748 A at 40 °C, derating to 667 A at 50 °C, and further to 580 A at 60 °C. The derating temperature threshold is 40 °C — above that ambient, the continuous current capability drops linearly. For a panel builder sizing the soft starter against a motor FLA, use the 40 °C figure as the base and apply the derating if the enclosure ambient runs hotter. ## System voltage and environmental rating Insulation voltage is rated 690 V, and the operating frequency covers 50 to 60 Hz. This matches standard European and North American line voltages up to 690 V phase-to-phase. The pollution degree is 3 per IEC 60947-4-2, meaning the device is designed for conductive pollution or dry non-conductive pollution that becomes conductive due to condensation — typical in industrial control panels without climate control. The soft starter includes integral motor overload protection and intrinsic device protection, which reduces the need for a separate overload relay in the motor branch circuit. Adjustable current limitation is also built in, allowing the starting current to be tuned to the load without external hardware. ## Panel integration and termination Mounting is screw fixing with a vertical mounting surface that allows +/-90° rotation and +/-22.5° tilt front-to-back. The envelope is 298 mm deep, 210 mm wide, and 230 mm high — confirm the enclosure depth accommodates the 298 mm plus clearance: 100 mm upwards, 75 mm downwards, and 5 mm at the side for ventilation. Main circuit termination accepts stranded 70...240 mm² or finely stranded 50...240 mm², with busbar connection as the listed method. For North American wire sizes, the clamping points accept 2/0 to 500 kcmil using both points, or 250...500 kcmil at the back point, and 3/0...600 kcmil at the front. ## Inside-delta wiring and thyristor control The 3RW4447-2BC35 supports inside-delta circuit configuration, which connects the soft starter's thyristors in the delta legs of a six-wire motor. This reduces the line current drawn through the soft starter to approximately 58% of the motor FLA, allowing a smaller-rated unit to control a larger motor. The thyristors are confirmed present — this is a standard silicon-controlled rectifier (SCR) design, not a hybrid or contactor-based soft starter. Minimum load is 8% of the rated current, meaning the soft starter can regulate down to that level without dropping out. The maximum motor cable length is 500 m — relevant for remote motor installations where long cable runs add capacitance and may cause nuisance tripping or ringing on the output.","metaTitle":"Siemens 3RW4447-2BC35 SIRIUS Soft Starter, 748 A, 690 V","metaDescription":"Siemens 3RW4447-2BC35 SIRIUS soft starter, 748 A at 40 °C, 690 V insulation, 50/60 Hz. Active production, sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"298mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"210mm","title":"3RW4447-2BC35","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter Values at 575 V, 50 °C standard: 385 A, 400 hp Inside-delta: 667 A, 750 hp 400-600 V AC, 115 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5547-2HA16<<","During Storage":"-25 ... +80°C","External Reset":"Yes","Finely Stranded":"50 ... 240 mm²","lifecycle_stage":"current","During Operation":"60°C","Fastening Method":"screw fixing","Minimum Load [%]":"8%","For Main Contacts":"2/0 ... 500 kcmil","Mounting Position":"with vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back","Product Brand Name":"SIRIUS","Degree Of Pollution":"3, acc. to IEC 60947-4-2","Product Designation":"Soft starter","Wire Length Maximum":"500m","Derating Temperature":"40°C","Inside-Delta Circuit":"Yes","at 50 Hz rated value":"115V","at 60 Hz rated value":"115V","at 40 °C rated value":"748A","at 50 °C rated value":"667A","at 60 °C rated value":"580A","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","Using The Back Clamping Point":"250 ... 500 kcmil","Insulation Voltage Rated Value":"690V","Using The Front Clamping Point":"3/0 ... 600 kcmil","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"Display","Integrated Bypass Contact System":"Yes","For Auxiliary And Control Circuit":"spring-loaded terminals","Product Component Motor Brake Output":"Yes","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":"Yes","at standard circuit at 40 °C rated value":"315kW","at standard circuit at 50 °C rated value":"400hp","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":"3","Type Of Voltage Of The Control Supply Voltage":"AC","at inside-delta circuit at 40 °C rated value":"500kW","at inside-delta circuit at 50 °C rated value":"750hp","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":"400 ... 600V","contact rating of auxiliary contacts according to UL":"B300 / R300","Operating Voltage At Inside-Delta Circuit Rated Value":"400 ... 600V","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":"232W","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":"86A","Relative Negative Tolerance Of The Operating Voltage At Inside-Delta Circuit":"-15%","Relative Positive Tolerance Of The Operating Voltage At Inside-Delta Circuit":"10%"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/b2cca824fa2cd472828a04dd9ebcd70f.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=178317&mlfb=3RW4447-2BC35"},"ai":{"faq":[{"question":"How can I get pricing and availability for the 3RW4447-2BC35?","answer":"No stock-holding claim is made here — availability is verified per inquiry."},{"question":"What is the 3RW4447-2BC35's depth?","answer":"The depth is 298 mm. Combined with a width of 210 mm and height of 230 mm, this defines the panel cutout and enclosure depth requirement. Allow 100 mm clearance above, 75 mm below, and 5 mm at the side for airflow."},{"question":"What compliance documentation does Siemens provide for the 3RW4447-2BC35?","answer":"The device is designed to IEC 60947-4-2 (pollution degree 3) and carries the SIRIUS brand. As a current-production Siemens industrial control product, it ships with a declaration of conformity covering the applicable EU directives (CE). RoHS and REACH compliance documentation is available from Siemens upon request — the part is manufactured after the RoHS exemption deadlines for industrial equipment."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4447-2BC35","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/3RW4447-2BC35 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}}