{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4427-3BC34","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4427-3BC34","canonicalUrl":"https://aoctrl.com/siemens/3RW4427-3BC34","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4427-3BC34","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4427-3BC34 soft starter, 161 A at 40 °C, 690 V insulation voltage, integrated bypass, inside-delta wiring, screw fixing, 270 mm depth.","salesMarkdown":"## Continuous duty current and the bypass reality The 3RW4427-3BC34: The integrated bypass contact system shorts the thyristors after the start ramp, so the steady-state current limit is set by the bypass contacts and the main circuit terminals, not the semiconductor junction temperature. In a panel that runs at 50 °C — common in a non-air-conditioned motor control center — budget for 142 A continuous, not the 40 °C nameplate figure. The minimum load is 8 % of the soft starter's rated current, which means it can soft-start a lightly loaded pump or fan without the output current oscillation that occurs with soft starters that have a higher minimum load threshold. ## Inside-delta wiring and panel space This soft starter supports inside-delta circuit wiring, which reduces the current the soft starter must carry to 58 % of the motor full-load current. For a given motor, you can select a smaller frame size than a line-connected soft starter would require. The trade-off is six motor leads instead of three, so the motor must have both ends of each winding accessible. The mounting is screw fixing, not DIN-rail snap-on. The envelope is 170 mm wide by 192 mm high by 270 mm deep. Clearance above the unit must be 100 mm and below 75 mm for natural convection cooling; side clearance is only 5 mm, so adjacent units can be packed tightly side-to-side. ## Termination and wiring The main current circuit uses box terminals accepting stranded wire from 4 to 50 mm². Two different termination systems — plan the wiring kit accordingly; the control wiring is tool-less push-in, but the power wiring needs a screwdriver. Maximum wire length between the soft starter and the motor is 500 m. Beyond that, reflected wave voltages at the motor terminals can exceed the winding insulation rating, especially on 480 V and 690 V systems. If the run is near the limit, add an output dV/dt filter. ## Lifecycle and sourcing The insulation voltage rating is 690 V, covering 400 V, 480 V, and 690 V systems. Pollution degree 3 per IEC 60947-4-2 means it is rated for conductive pollution environments typical of industrial control panels without climate control.","metaTitle":"Siemens 3RW4427-3BC34 Soft Starter, SIRIUS, 161 A at 40 °C","metaDescription":"Siemens 3RW4427-3BC34 SIRIUS soft starter, 161 A at 40 °C, integrated bypass, inside-delta capable. Active production, sourced to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"270mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"170mm","title":"3RW4427-3BC34","Height":"192mm","Upwards":"100mm","Stranded":"2x (4 ... 50 mm²)","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter Values at 460 V, 50 °C standard: 82 A, 60 hp Inside-delta: 142 A, 100 hp 200-460 V AC, 115 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5527-3HA14<<","During Storage":"-25 ... +80°C","External Reset":"Yes","lifecycle_stage":"current","During Operation":"60°C","Fastening Method":"screw fixing","Minimum Load [%]":"8%","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":"161A","at 50 °C rated value":"142A","at 60 °C rated value":"125A","For Auxiliary Contacts":"2x (24 ... 16)","For Main Current Circuit":"box terminal","Motor Overload Protection":"Yes","Using Both Clamping Points":"2x (10 ... 1/0)","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Using The Back Clamping Point":"10 ... 2/0","Insulation Voltage Rated Value":"690V","Using The Front Clamping Point":"10 ... 2/0","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":"45kW","at standard circuit at 50 °C rated value":"60hp","Finely Stranded Without Core End Processing":"2x (4 ... 35 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":"90kW","at inside-delta circuit at 50 °C rated value":"100hp","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":"55W","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":"18A","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/4eda0a72d0693ce29a7c1d9949ca92e3.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=212625&mlfb=3RW4427-3BC34"},"ai":{"faq":[{"question":"What is the continuous current rating of the 3RW4427-3BC34 at typical panel temperatures?","answer":"At 40 °C ambient the continuous rating is 161 A. The integrated bypass carries the steady-state current, so these figures reflect the bypass contact and terminal rating, not the thyristor junction temperature."},{"question":"Can the 3RW4427-3BC34 be wired in inside-delta configuration?","answer":"Yes, it supports inside-delta wiring, which reduces the current through the soft starter to 58 % of the motor full-load current. This allows a smaller frame size for a given motor, provided the motor has both ends of each winding accessible."},{"question":"What clearance is needed around the 3RW4427-3BC34 in the panel?","answer":"100 mm above and 75 mm below for convection cooling, with only 5 mm side clearance. The mounting is screw fixing, not DIN-rail, so the backplate must be drilled for the mounting holes."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4427-3BC34","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/3RW4427-3BC34 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}}