{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4455-2BC44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4455-2BC44","canonicalUrl":"https://aoctrl.com/siemens/3RW4455-2BC44","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4455-2BC44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4455-2BC44 soft starter, 1200 A at 40 °C, 690 V insulation voltage, 50/60 Hz, integrated bypass, screw fixing.","salesMarkdown":"## 1200 A at 40 °C — sizing this soft starter for the motor The 3RW4455-2BC44: Rated 1200 A at 40 °C ambient, this SIRIUS soft starter handles large motor loads — think pumps, conveyors, or compressors in the 600–800 kW range depending on voltage and service factor. Derate to 1065 A at 50 °C and 954 A at 60 °C — the 40 °C derating temperature means the full 1200 A is only available below that threshold; above it, the current ceiling drops. The 690 V rated insulation voltage (IEC 60947-4-2) and pollution degree 3 suit industrial panels where conductive dust or humidity is present — common in heavy manufacturing. ## Integrated bypass and inside-delta wiring — what it means for the panel An integrated bypass contact system means the thyristors are shorted out after start, eliminating heat dissipation from the silicon during run — the panel's cooling requirement drops significantly. Inside-delta circuit capability lets you wire the soft starter in the delta leg of a six-lead motor, reducing the unit's current rating requirement to 58% of the motor FLA — useful for retrofitting into existing motor circuits without upsizing the starter. Main current circuit connects via busbar (not cable lugs), and the main contacts accept 2/0 to 500 kcmil — expect to terminate with busbar kits, not compression lugs. ## Mounting and clearances — fitting the 640 mm tall unit At 640 mm height, 510 mm width, and 290 mm depth, this is a floor-mount or large enclosure unit — not a DIN-rail candidate. Fastening is by screw fixing, not snap-on. Mounting position allows vertical surface with +/-90° rotation and +/-22.5° tilt forward/back — the enclosure layout must accommodate the swing arc, not just the footprint. Minimum clearances: 100 mm above, 75 mm below, 5 mm at the sides — the top clearance is for cable entry and heat plume; the 5 mm side gap is tight, so adjacent devices must not block ventilation. ## Protection and control features built in Motor overload protection is integrated — no separate overload relay needed in the power circuit. Intrinsic device protection covers the thyristors against over-temperature and over-current. Adjustable current limitation lets you set the start current between 8% and 100% of the unit's rating — the 8% minimum load means it can soft-start very lightly loaded motors without hunting. External reset input and a display for fault signals give the panel builder a local HMI point without opening the enclosure door. A motor brake output component is included — if the motor has a DC brake, this starter can control it directly, saving a separate contactor. ## Cable sizing and connection notes Main circuit power cables: stranded 70 to 240 mm² or finely stranded 50 to 240 mm² — the finely stranded range starts lower because the finer strands fill the lug better at smaller cross-sections. Maximum motor cable length is 500 m — beyond that, capacitive charging current from the cable can interfere with the thyristor firing or cause nuisance trips on the overload detection.","metaTitle":"Siemens 3RW4455-2BC44 Soft Starter, 1200 A, SIRIUS","metaDescription":"Siemens 3RW4455-2BC44 SIRIUS soft starter, 1200 A at 40 °C, 690 V insulation, integrated bypass. Current lifecycle. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"290mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"510mm","title":"3RW4455-2BC44","Height":"640mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter Values at 400 V, 40 °C standard: 693 A, 400 kW Inside-delta: 1200 A, 710 kW 200-460 V AC, 230 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5553-2HA14<<","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":"230V","at 60 Hz rated value":"230V","at 40 °C rated value":"1 200A","at 50 °C rated value":"1 065A","at 60 °C rated value":"954A","For Auxiliary Contacts":"2x (24 ... 16)","For Main Current Circuit":"busbar connection","Motor Overload Protection":"Yes","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Insulation Voltage Rated Value":"690V","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":"400kW","at standard circuit at 50 °C rated value":"500hp","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":"710kW","at inside-delta circuit at 50 °C rated value":"950hp","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","Operating Voltage At Inside-Delta Circuit Rated Value":"200 ... 460V","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":"220W","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":"138A","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/b312c4d596cb278d81cb35ff6dd59577.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=356365&mlfb=3RW4455-2BC44"},"ai":{"faq":[{"question":"What is the closest alternative to 3RW4455-2BC44 in the SIRIUS family?","answer":"The 3RW4455-2BC44 is a specific current rating (1200 A) with integrated bypass and inside-delta capability; a different rating would require a different order code within the SIRIUS 3RW44 series."},{"question":"What compliance documentation does Siemens provide for 3RW4455-2BC44?","answer":"The unit is designed to IEC 60947-4-2 (pollution degree 3). Standard Siemens documentation includes the CE declaration of conformity and the product manual. RoHS and REACH compliance is standard for current-production SIRIUS devices."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4455-2BC44","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/3RW4455-2BC44 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T19:47:38.189Z","lastPublished":"2026-07-22T19:47:38.189Z","indexable":true}}