How to Select and Size a Soft Starter for a Motor
How to size a soft starter correctly by full-load current, IEC 60947-4-2 duty class, starting torque against the load, control method, wiring topology and...
Siemens 3RW40 soft starters are advanced compact motor starting solutions designed for smooth starting and stopping of three-phase asynchronous motors in industrial applications. The 3RW40 series focuses on reducing mechanical stress, limiting inrush current, and providing enhanced motor protection compared to basic soft starters. With integrated bypass functionality and flexible configuration options, Siemens 3RW40 soft starters are well suited for pumps, fans, compressors, conveyors, and general industrial machinery requiring reliable and efficient motor starting.
The Siemens 3RW4024-1BB14 is a SIRIUS 3RW40 motor soft starter rated for 12.5 A and specified for a motor power rating of 5.5 kW (reference rating at 400 V). It is designed for three-phase supply voltages from 200 to 480 V AC, making it suitable for common industrial voltage classes. Typical motor compatibility includes small to medium three-phase asynchronous motors used on pumps, fans, compressors and conveyor drives where a 5.5 kW rating or nearby frame sizes apply. This SKU features two‑phase (polarity balancing) control to minimise DC components during starting, integrated bypass contacts to remove semiconductor losses after start-up, and built-in device protection functions to reduce the need for separate overload protection. The unit accepts a control supply on screw terminals (110–230 V AC/DC as supplied in this product configuration) and is supplied in an IP20 enclosure for panel mounting. Use cases include replacing DOL or wye–delta starting for reduced mechanical shock, limiting inrush current on weak supplies, and providing a compact soft start solution where panel space is limited.
| product brand name | SIRIUS |
|---|---|
| product designation | Soft starter |
| product feature: integrated bypass contact system | Yes |
| product feature: thyristors | Yes |
| product function: intrinsic device protection | Yes |
| product function: motor overload protection | Yes |
| product function: evaluation of thermistor motor protection | No |
| product function: external reset | Yes |
| product function: adjustable current limitation | Yes |
| product function: inside-delta circuit | No |
| product component motor brake output | No |
| insulation voltage rated value | 600 V |
| degree of pollution | 3, acc. to IEC 60947-4-2 |
| blocking voltage of the thyristor maximum | 1 600 V |
| reference code according to EN 61346-2 | Q |
| reference code according to DIN 40719 extended according to IEC 204-2 according to IEC 750 | G |
| operational current: at 40 °C rated value | 12.5 A |
|---|---|
| operational current: at 50 °C rated value | 11 A |
| operational current: at 60 °C rated value | 10 A |
| at 230 V: at standard circuit at 40 °C rated value | 3 kW |
| at 400 V: at standard circuit at 40 °C rated value | 5.5 kW |
| yielded mechanical performance [hp] for 3-phase AC motor at 200/208 V at standard circuit at 50 °C rated value | 3 hp |
| operating frequency rated value | 50 ... 60 Hz |
| relative negative tolerance of the operating frequency | -10 % |
| relative positive tolerance of the operating frequency | 10 % |
| operating voltage at standard circuit rated value | 200 ... 480 V |
| relative negative tolerance of the operating voltage at standard circuit | -15 % |
| relative positive tolerance of the operating voltage at standard circuit | 10 % |
| minimum load [%] | 20 % |
| adjustable motor current for motor overload protection minimum rated value | 5 A |
| continuous operating current [% of Ie] at 40 °C | 115 % |
| power loss [W] at operational current at 40 °C during operation typical | 2 W |
| type of voltage of the control supply voltage | AC/DC |
|---|---|
| control supply voltage frequency 1 rated value | 50 Hz |
| control supply voltage frequency 2 rated value | 60 Hz |
| relative negative tolerance of the control supply voltage frequency | -10 % |
| relative positive tolerance of the control supply voltage frequency | 10 % |
| control supply voltage 1 at AC at 50 Hz | 110 ... 230 V |
| control supply voltage 1 at AC at 60 Hz | 110 ... 230 V |
| relative negative tolerance of the control supply voltage at AC at 50 Hz | -15 % |
| relative positive tolerance of the control supply voltage at AC at 50 Hz | 10 % |
| control supply voltage 1 at DC | 110 ... 230 V |
| display version for fault signal | red |
| Part number | 3RW4024-1BB14 |
|---|---|
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Active, in production |
| EAN | 4011209691582 |
| ETIM class | EC000640 |
| eCl@ss | 27370907 |
| size of engine control device | S0 |
|---|---|
| width | 45 mm |
| height | 125 mm |
| depth | 155 mm |
| fastening method | screw and snap-on mounting |
| 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 |
| required spacing with side-by-side mounting: upwards | 60 mm |
| required spacing with side-by-side mounting: at the side | 15 mm |
| required spacing with side-by-side mounting: downwards | 40 mm |
| wire length maximum | 300 m |
| number of poles for main current circuit | 3 |
| type of electrical connection: for main current circuit | screw-type terminals |
|---|---|
| type of electrical connection: for auxiliary and control circuit | screw-type terminals |
| number of NC contacts for auxiliary contacts | 0 |
| number of NO contacts for auxiliary contacts | 2 |
| number of CO contacts for auxiliary contacts | 1 |
| type of connectable conductor cross-sections for main contacts for box terminal using the front clamping point: finely stranded with core end processing | 2x (1 ... 2.5 mm2), 2x (2.5 ... 6 mm2) |
| type of connectable conductor cross-sections for AWG cables for main contacts for box terminal: using the front clamping point | 1x 8, 2x (16 ... 10) |
| type of connectable conductor cross-sections for auxiliary contacts: solid | 2x (0.5 ... 2.5 mm2) |
| installation altitude at height above sea level | 5 000 m |
|---|---|
| environmental category: during transport according to IEC 60721 | 2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m) |
| environmental category: during storage according to IEC 60721 | 1K6 (only occasional condensation), 1C2 (no salt mist), 1S2 (sand must not get inside the devices), 1M4 |
| environmental category: 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 |
| ambient temperature: during operation | -25 ... +60 °C |
| ambient temperature: during storage | -40 ... +80 °C |
| derating temperature | 40 °C |
| protection class IP on the front according to IEC 60529 | IP20 |
| touch protection on the front according to IEC 60529 | finger-safe, for vertical contact from the front |
| at 220/230 V: at standard circuit at 50 °C rated value | 3 hp |
|---|---|
| at 460/480 V: at standard circuit at 50 °C rated value | 7.5 hp |
| contact rating of auxiliary contacts according to UL | B300 / R300 |
| Environmental Product Declaration: global warming potential [CO2 eq] / during manufacturing | 4.24 kg |
|---|
| Net weight | 0.687 kg |
|---|---|
| Package dimensions | 182 × 155 × 58 mm |
| Country of origin | CZ |
| Shipping weight | 1.187 kg |
| Ships from | Türkiye |
| Dispatch | 12 Nov |
| Stock | In stock |
Source: manufacturer data · Last verified: 30 Oct 2026
No documents are on file for this part yet.
Ask us for the datasheetThe rated current of 3RW4024-1BB14 is 12.5 A.
The rated operational voltage of 3RW4024-1BB14 is 200–480 V AC.
The rated motor power of 3RW4024-1BB14 is 5.5 kW.
The control voltage range of 3RW4024-1BB14 is 110–230 V.
The tariff (HS) code on file for 3RW4024-1BB14 is 853710.
The EAN (GTIN) of 3RW4024-1BB14 is 4011209691582.
3RW4024-1BB14 ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival. Stock items are dispatched within 1–2 business days.
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