{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4074-6BB34","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4074-6BB34","canonicalUrl":"https://aoctrl.com/siemens/3RW4074-6BB34","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4074-6BB34","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4074-6BB34 soft starter, Size S12, 280 A at 40 °C, 50/60 Hz, 115 V control voltage, screw fixing, busbar connection.","salesMarkdown":"## What the 280 A rating means for motor sizing The 3RW4074-6BB34: The 280 A at 40 °C is the continuous rated current for the soft starter's main thyristors — this is the number you size against the motor FLA, not the upstream breaker. The derating temperature is 40 °C, meaning the full 280 A is only available up to that ambient; above it the current drops per the datasheet curve. The adjustable current limitation lets you set a starting current ceiling below the motor's locked-rotor draw — useful when the supply transformer or generator is undersized and you need to limit voltage dip during start. Minimum load is 20%, so it handles lightly loaded motors without dropping out. ## Panel integration and wiring constraints Size S12 means a 230 mm height, 160 mm width, and 278 mm depth — that's a substantial block, so plan the enclosure depth accordingly. Screw fixing to the mounting plate, not DIN rail; the fastening method is four screws into the back panel. Clearance: 100 mm above, 75 mm below, 5 mm at the sides — the side gap is tight, so adjacent components need to be low-heat or spaced further if the ambient stacks. Main circuit termination is busbar connection — not cable lugs on the standard version. Stranded wire range is 70 to 240 mm², finely stranded 50 to 240 mm². For the US market, the main contacts accept 2/0 to 500 kcmil, with the back clamping point taking 250 to 500 kcmil and the front clamping point 3/0 to 600 kcmil. ## Environmental and protection features Pollution degree 3 per IEC 60947-4-2 — that's the industrial environment with conductive pollution, so no additional conformal coating is required for typical panel conditions. Insulation voltage rated 600 V. Motor overload protection is built in — no separate overload relay needed. Intrinsic device protection covers the soft starter's own thyristors against over-temperature and over-current. External reset allows remote fault recovery without opening the panel door.","metaTitle":"Siemens 3RW4074-6BB34 SIRIUS Soft Starter, 280A at 40°C","metaDescription":"Siemens 3RW4074-6BB34 SIRIUS soft starter, 280A rated at 40°C, Size S12 frame, active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"278mm","Solid":"2x (0.5 ... 2.5 mm²)","Width":"160mm","title":"3RW4074-6BB34","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S12 248 A, 200 hp/460 V, 50 °C 200-460 V AC, 115 V AC Screw terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5074-6AB14<<","During Storage":"-40 ... +80°C","External Reset":"Yes","Finely Stranded":"50 ... 240 mm²","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw fixing","Minimum Load [%]":"20%","For Main Contacts":"2/0 ... 500 kcmil","Mounting Position":"With additional fan: With vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back Without additional fan: With vertical mounting surface +/-10° rotatable, with vertical mounting surface +/- 10° t","Product Brand Name":"SIRIUS","Degree Of Pollution":"3, acc. to IEC 60947-4-2","Product Designation":"Soft starter","Wire Length Maximum":"300m","Derating Temperature":"40°C","Inside-Delta Circuit":"No","at 50 Hz rated value":"115V","at 60 Hz rated value":"115V","at 40 °C rated value":"280A","at 50 °C rated value":"248A","at 60 °C rated value":"215A","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","Size Of Engine Control Device":"S12","Using The Back Clamping Point":"250 ... 500 kcmil","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"3/0 ... 600 kcmil","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"red","Integrated Bypass Contact System":"Yes","For Auxiliary And Control Circuit":"screw-type terminals","Product Component Motor Brake Output":"No","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":"No","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":"2","Type Of Voltage Of The Control Supply Voltage":"AC","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","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":"90W","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":"130A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/863154563ecb878e7dd48de7f1119947.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=75659&mlfb=3RW4074-6BB34"},"ai":{"faq":[{"question":"What is the maximum wire length for the 3RW4074-6BB34?","answer":"The maximum wire length between the soft starter and the motor is 300 m. This is the total cable run, not per phase — longer runs increase voltage drop and may cause nuisance tripping on the internal protection."},{"question":"Does the 3RW4074-6BB34 support inside-delta connection?","answer":"No, the inside-delta circuit is not supported. This unit is designed for standard in-line connection between the supply and the motor terminals."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4074-6BB34","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/3RW4074-6BB34 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}}