{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4445-2BC45","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4445-2BC45","canonicalUrl":"https://aoctrl.com/siemens/3RW4445-2BC45","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4445-2BC45","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4445-2BC45 soft starter, 542 A at 40 °C, 690 V insulation voltage, 50/60 Hz, screw fixing, 298 mm depth, 210 mm width, 230 mm height.","salesMarkdown":"## Panel fit and mounting — 298 × 210 × 230 mm The 3RW4445-2BC45 occupies a 298 mm depth, 210 mm width, and 230 mm height envelope — a substantial footprint that requires a dedicated backpanel area in the cabinet. Mounting is by screw fixing, not DIN rail; the unit accepts a vertical mounting surface with ±90° rotation and ±22.5° tilt forward or backward, so the panel layout must account for the orientation range during installation. Clearance requirements: 100 mm above, 75 mm below, and only 5 mm at the sides — this tight side clearance means adjacent components can sit close, but the vertical airflow path needs the full 100/75 mm free space for convection cooling. ## Current derating and thermal budget — 542 A at 40 °C baseline The insulation voltage is rated 690 V, and the operating frequency covers 50 to 60 Hz, so the unit suits standard three-phase motor supplies across global line voltages up to 690 V. Derating temperature is specified at 40 °C — above this, the continuous current rating follows the published curve; the device also includes intrinsic device protection and motor overload protection, meaning no separate overload relay is needed for the motor branch. ## Inside-delta circuit and adjustable current limitation The 3RW4445-2BC45 supports inside-delta wiring, which reduces the current through the thyristors to 58 % of the line current — a key feature for large motors where the soft starter can be downsized relative to the motor FLA when wired in this configuration. Adjustable current limitation lets the commissioning engineer set the start current between 8 % and 100 % of the rated current — the 8 % minimum load capability means the starter handles light-load applications without dropping out. Thyristor-based switching (no contactor bypass built in) means the power semiconductors handle the full start and run current; an external bypass contactor can be added for continuous-duty efficiency, but the unit itself is rated for continuous thyristor conduction. ## Termination and wiring — main circuit busbar, auxiliary screw clamps Main current circuit connections use busbar terminals, accepting stranded wire from 70 to 240 mm² and finely stranded from 50 to 240 mm², or kcmil sizes from 2/0 to 500 kcmil using both clamping points. The front clamping point accepts 3/0 to 600 kcmil; the back clamping point accepts 250 to 500 kcmil — useful when paralleling cables for high-current runs. Auxiliary control wiring uses screw terminals accepting solid wire 0.25 to 1.5 mm² or stranded 24 to 16 AWG — standard for the 24 VDC control loop. Maximum motor cable length is 500 m — sufficient for most industrial installations; longer runs may require output reactors to limit reflected wave stress on the motor insulation. ## Environmental and protection ratings Operating temperature range during operation is up to 60 °C ambient; storage range is -25 to +80 °C — qualification engineers should note the storage limits for spares holding. The unit includes a display for fault signalling and supports external reset — useful for remote fault acknowledgement in automated lines.","metaTitle":"Siemens 3RW4445-2BC45 SIRIUS Soft Starter, 542A at 40°C","metaDescription":"Siemens 3RW4445-2BC45 SIRIUS soft starter, 542A rated at 40°C, 690V insulation, inside-delta circuit, 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":"3RW4445-2BC45","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: 313 A, 200 kW Inside-delta: 542 A, 355 kW 400-600 V AC, 230 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5545-2HA16<<","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":"230V","at 60 Hz rated value":"230V","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":"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":"3","Type Of Voltage Of The Control Supply Voltage":"AC","at inside-delta circuit at 40 °C rated value":"355kW","at inside-delta circuit at 50 °C rated value":"500hp","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":"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/8cdcac0c46e0f25e274073d9637df5f8.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=16269&mlfb=3RW4445-2BC45"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4445-2BC45","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/3RW4445-2BC45 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}}