{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4444-6BC45","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4444-6BC45","canonicalUrl":"https://aoctrl.com/siemens/3RW4444-6BC45","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4444-6BC45","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4444-6BC45 soft starter, 433 A at 40 °C, 690 V insulation voltage, 50…60 Hz, inside-delta circuit capable, screw fixing.","salesMarkdown":"## Active production — what that means for procurement The 3RW4444-6BC45: No stock-holding claim is made here; the page exists to initiate that procurement conversation. ## Current derating and ambient heat — the real operating envelope Rated 433 A at 40 °C ambient — that is the reference point for sizing. For a steel-mill environment where cabinet ambient near the drives can hit 50–60 °C, the 320 A figure at 60 °C is the one to design to, not the 40 °C number. The derating temperature is specified at 40 °C, which means above that the unit must be downrated per the published curve. If your panel pulls radiant heat from adjacent rolls or furnaces, budget the 60 °C column — 320 A continuous is the safe ceiling. ## Inside-delta wiring and minimum load — what it handles Inside-delta circuit capability means the soft starter's thyristors are wired in the delta legs of the motor, not in the supply lines. This reduces the current through each thyristor branch to 58% of the line current — a common topology for high-current soft starters above 300 A where standard in-line thyristor stacks would be oversized. Minimum load is 8% — the soft starter needs at least that fraction of its rated current to maintain proper firing angle detection. Below 8%, the thyristor gate pulses may not latch reliably, so verify the motor no-load current against the 433 A rating before committing. ## Mounting and panel fit — screw fixing with rotation allowance Fastening method is screw fixing, not DIN-rail snap-on. Dimensions: 230 mm height, 210 mm width, 298 mm depth. Clearance requirements: 100 mm above, 75 mm below, 5 mm at the sides. The 100 mm upward gap is for cable bending radius on the busbar connection — the main current circuit uses busbars, not cables, so the vertical clearance is driven by busbar standoffs, not wire loops. ## Wiring terminations — main and control circuits Main current circuit termination is busbar connection with stranded cable options 70…240 mm² and finely stranded 50…240 mm². For North American installations, the busbar clamping points accept 2/0…500 kcmil using both clamping points, or 250…500 kcmil using the back clamping point alone. The auxiliary contact terminals are sized for standard control wiring — no special crimp tooling needed beyond a standard ferrule kit. Maximum wire length from the soft starter to the motor is 500 m. Beyond that, voltage drop on the thyristor firing pulses and cable capacitance can cause misfiring — keep the run under 500 m, or add a line reactor at the soft starter output. ## Protection and diagnostics — overload, current limit, fault display Motor overload protection is integrated — no separate overload relay needed downstream. Adjustable current limitation lets you set the start current between 0 and the rated value, which is the primary parameter for tuning the acceleration ramp on high-inertia loads like conveyors or crushers. Intrinsic device protection monitors the thyristor junction temperature and triggers a fault if the thermal budget is exceeded — this is separate from motor overload. The fault signal is shown on a display with external reset capability, so a line-down fault can be cleared remotely without opening the panel door.","metaTitle":"Siemens 3RW4444-6BC45 SIRIUS Soft Starter, 433A, 690V","metaDescription":"Siemens 3RW4444-6BC45 SIRIUS soft starter, 433A at 40°C, 690V insulation, 50/60 Hz. Active production, quoted to order. Inquire for pricing and lead time.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"298mm","Solid":"2x (0.5 ... 2.5 mm²)","Width":"210mm","title":"3RW4444-6BC45","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter Values at 500 V, 40 °C standard: 250 A, 160 kW Inside-delta: 433 A, 315 kW 400-600 V AC, 230 V AC Screw terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5544-6HA16<<","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":"433A","at 50 °C rated value":"372A","at 60 °C rated value":"320A","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","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":"screw-type 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 (0.5 ... 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":"160kW","at standard circuit at 50 °C rated value":"200hp","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":"315kW","at inside-delta circuit at 50 °C rated value":"350hp","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%","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":"110W","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":"50A","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/3ef224ba0b2b53e7cb9c8a67a905ff73.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=444691&mlfb=3RW4444-6BC45"},"ai":{"faq":[{"question":"What is the current rating at different ambient temperatures?","answer":"433 A at 40 °C, 372 A at 50 °C, and 320 A at 60 °C. The derating temperature threshold is 40 °C; above that, use the lower figures for panel sizing."},{"question":"Can 3RW4444-6BC45 be wired in inside-delta configuration?","answer":"Yes, it supports inside-delta circuit wiring. This places the thyristors in the motor delta legs, reducing branch current to 58% of line current — standard practice for high-current soft starters."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4444-6BC45","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/3RW4444-6BC45 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}}