{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4445-2BC34","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4445-2BC34","canonicalUrl":"https://aoctrl.com/siemens/3RW4445-2BC34","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4445-2BC34","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4445-2BC34 soft starter, 542 A at 40 °C, 690 V insulation voltage, 50/60 Hz, inside-delta circuit, adjustable current limitation, display for fault signal, screw fixing.","salesMarkdown":"## Rated current and thermal derating — what the numbers mean for a motor start The 3RW4445-2BC34: For a panel sitting in a 50 °C environment — common in a packed MCC lineup — the usable continuous motor current drops to 485 A, so the motor FLA must stay under that ceiling, not the 40 °C figure. The minimum load threshold is 8 % of the rated current — below that the starter may not reliably detect the motor's running state. This matters for lightly loaded pumps or unloaded conveyors where the start current barely exceeds the no-load draw. ## Inside-delta wiring and adjustable current limitation This soft starter supports an inside-delta circuit configuration, which reduces the current through the thyristors to 58 % of the line current. For a 542 A motor, the thyristors see about 315 A, letting you use a smaller frame than a standard in-line connection would require. Adjustable current limitation lets you set the start current between the motor's no-load and locked-rotor values, so you can tune the ramp for a soft start on a conveyor or a hard start on a loaded crusher without swapping hardware. ## Termination and mounting — what fits in the cabinet Main power connections accept stranded 70–240 mm² or 2/0–500 kcmil copper, with a busbar connection option for the main current circuit. The front clamping point handles up to 600 kcmil; the back point takes 250–500 kcmil. For dual-cable runs, both clamping points together accept 2x 2/0 to 2x 500 kcmil. Auxiliary control wiring uses solid 0.25–1.5 mm² or stranded 24–16 AWG. The mounting position allows vertical surface mounting with ±90° rotation and ±22.5° tilt front-to-back — useful when the starter sits on a swing-out panel or a slanted enclosure backplate. Dimensions are 230 mm high, 210 mm wide, 298 mm deep. Clearance requirements: 100 mm above, 75 mm below, 5 mm at the sides. The 298 mm depth means the starter extends nearly 300 mm into the cabinet — check the enclosure depth before laying out the backplate. ## Protection and environmental ratings Built-in motor overload protection and intrinsic device protection (thyristor overtemperature, phase imbalance, load-wire break) are standard. The pollution degree is 3 per IEC 60947-4-2, meaning the unit tolerates conductive dust and condensation typical in industrial environments without conformal coating on the power board. Insulation voltage is rated 690 V, so the starter can run on 480 V or 600 V systems with margin. Operating frequency covers 50–60 Hz without a jumper change. Storage temperature range is -25 to +80 °C; operating ambient max is 60 °C. A display provides fault-signal readout — no need to carry a laptop to the panel for a blink code; the display shows the trip cause directly.","metaTitle":"Siemens 3RW4445-2BC34 SIRIUS Soft Starter, 542 A at 40 °C","metaDescription":"Siemens 3RW4445-2BC34 SIRIUS soft starter, 542 A at 40 °C, 690 V insulation, inside-delta circuit, adjustable current limitation.","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":"3RW4445-2BC34","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter Values at 460 V, 50 °C standard: 280 A, 200 hp Inside-delta: 485 A, 400 hp 200-460 V AC, 115 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5545-2HA14<<","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":"115V","at 60 Hz rated value":"115V","at 40 °C rated value":"542A","at 50 °C rated value":"485A","at 60 °C rated value":"433A","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":"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":"400hp","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":"145W","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":"62A","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/80e3d43baa874cc86917a768128c090b.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=300709&mlfb=3RW4445-2BC34"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4445-2BC34","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/3RW4445-2BC34 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}}