Siemens 3RW5247-6AC14 Heavy Duty Siemens Soft Starter 470A 250kW

The Siemens 3RW5247-6AC14 is a heavy-duty soft starter designed for demanding industrial applications, offering smooth acceleration and deceleration of motor loads. This robust unit provides significant advantages, including reduced mechanical stress on machinery, minimized inrush current to protect electrical infrastructure, and enhanced system reliability. Its core features encompass integrated bypass, advanced motor protection, and communication capabilities, positioning it as a premium solution for critical motor control scenarios. Key technical parameters include a rated operational voltage of 690V, a rated operational current of 470A, and a rated motor power of 250kW at 690V.

Product Specifications

| Parameter                  | Value                          |

| :------------------------- | :----------------------------- |

| Manufacturer               | Siemens                        |

| Product Series             | 3RW5 High Performance          |

| Model Number               | 3RW5247-6AC14                  |

| Rated Operational Voltage  | 690 V AC                       |

| Rated Operational Current  | 470 A                          |

| Rated Motor Power (690V)   | 250 kW                         |

| Enclosure Type             | IP20                           |

| Communication Interface    | PROFINET/PROFIBUS (optional)   |

| Control Voltage            | 110-250 V AC/DC                |

| Soft Starter Type          | High Performance               |

| Integrated Bypass          | Yes                            |

| Overload Protection        | Yes, Adjustable                |

| Dimensions (H x W x D)     | 450 x 200 x 235 mm             |

| Ambient Operating Temp.    | -25 to +60 °C                  |

Core Features & Market Positioning

The Siemens 3RW5247-6AC14 distinguishes itself through its integrated bypass, which ensures full mains voltage is available once the motor reaches operating speed, thereby reducing heat generation and increasing efficiency. This high-performance soft starter incorporates sophisticated electronic overload protection, offering precise motor safeguarding against thermal stress, phase unbalance, and stalls, exceeding the capabilities of traditional thermal overload relays. Its advanced control algorithms provide optimal torque control, minimizing mechanical shock during start-up and shutdown, which is crucial for extending the lifespan of pumps, fans, compressors, and conveyor systems. Market positioning is firmly within the premium segment, targeting applications where reliability, efficiency, and advanced control are paramount, often outperforming standard motor starters and competing directly with variable frequency drives in specific scenarios where precise speed control is not required.

Key Application Scenarios

This heavy-duty soft starter is ideally suited for applications involving high-inertia loads or those requiring controlled acceleration to prevent system shocks. Common use cases include the smooth starting of large centrifugal pumps in water treatment plants or oil and gas facilities, where rapid pressure surges must be avoided. It is also extensively used for fan systems in HVAC and industrial ventilation, reducing mechanical stress on fan blades and bearings, and minimizing power consumption during startup. Furthermore, the 3RW5247-6AC14 is an excellent choice for large conveyor belt systems in mining or material handling, ensuring gradual load engagement and preventing slippage or component damage. Its robust design also makes it suitable for compressors in heavy industry, where controlled ramp-up prevents excessive electrical surges.

Practical System Integration Guidance

Integrating the Siemens 3RW5247-6AC14 into existing industrial control systems is streamlined through its flexible connectivity options. The unit supports direct line connection for power circuits, with clear terminal markings for incoming L1, L2, L3 and outgoing T1, T2, T3. For control circuits, a universal control voltage input accepts a wide range of AC/DC voltages (110-250V), simplifying wiring across different control panels. Optional communication modules, such as PROFINET or PROFIBUS, enable seamless integration into SCADA or DCS environments for remote monitoring, diagnostics, and parameter adjustment. Wiring diagrams typically show the main power terminals connected directly to the motor, with the bypass contactor integrated within the soft starter's design.

Operation and Risk Mitigation

Operating the Siemens 3RW5247-6AC14 involves setting initial motor parameters and desired start-up characteristics via its intuitive interface or through connected communication protocols. Risk mitigation is a core design principle; the integrated electronic overload protection offers advanced diagnostics and trip functions, preventing motor damage from overcurrent or phase loss. The soft-start functionality inherently reduces mechanical shock, thus lowering the risk of equipment failure and associated downtime. In case of faults, the device provides detailed diagnostic information and error codes, aiding rapid troubleshooting. Common fault codes might relate to overload conditions, internal device faults, or communication errors, all of which are detailed in the comprehensive user manual.

Scalability & Long-Term Value

The Siemens 3RW5247-6AC14 offers significant long-term value through its robust construction and compatibility with Siemens' broader industrial automation portfolio. While it is a standalone soft starter, its communication capabilities allow it to be a node within larger industrial control networks, including those leveraging Industry 4.0 principles. Integration with Siemens' SIMATIC PLCs and HMI panels allows for centralized control and data acquisition, enabling predictive maintenance strategies and operational optimization. The inherent durability and advanced protection features contribute to extended motor and system lifespan, reducing total cost of ownership over the product's service life.

FAQs

What is the primary function of the Siemens 3RW5247-6AC14 soft starter?

It smoothly controls the start-up and stop of electric motors. This reduces mechanical stress on connected equipment like pumps and conveyors.

It also limits the inrush current, protecting the power supply and reducing voltage dips during motor startup. This enhances overall system stability and electrical infrastructure longevity.

The integrated bypass function allows for energy savings during steady-state operation and ensures full mains voltage is available once the motor is up to speed.

What are the main technical specifications for the 3RW5247-6AC14?

This unit has a rated operational voltage of 690V AC. Its maximum rated operational current is 470A.

It is designed for motors up to 250kW at 690V, making it suitable for heavy-duty applications. The enclosure is IP20 rated for protection against solid objects.

Control voltage is flexible, accepting 110-250V AC/DC. Ambient operating temperatures range from -25 to +60 °C for demanding environments.

How does the Siemens 3RW5247-6AC14 integrate into a control system?

Direct wiring connects the main power terminals to the motor and incoming power supply. Control voltage can be wired to its flexible input terminals.

Optional communication modules, such as PROFINET or PROFIBUS, allow integration into DCS or SCADA systems for remote control and monitoring.

This facilitates advanced diagnostics, parameter adjustments, and inclusion in overarching automation strategies for enhanced operational visibility.

What type of motor loads is this soft starter best suited for?

It is ideal for high-inertia loads that require a gradual ramp-up. This includes large pumps and fans in industrial settings.

Applications like compressors and heavy-duty conveyor systems benefit from its controlled acceleration and deceleration features. This minimizes operational shocks.

Its robust design ensures reliable performance even under challenging conditions common in sectors like manufacturing or water treatment.

What are the key advantages of using this Siemens soft starter over a direct-on-line starter?

It significantly reduces mechanical shock during motor startup, extending equipment lifespan. It also prevents damaging torque surges.

The substantial reduction in inrush current protects the electrical grid from voltage dips and reduces stress on power distribution components.

It provides advanced motor protection features, including electronic overload and phase loss detection, which are often absent or less sophisticated in DOL starters.

How does the integrated bypass feature benefit the system?

The bypass contactor closes once the motor reaches nominal speed, allowing full line voltage to be applied directly to the motor. This bypasses the power electronics.

Bypassing reduces heat dissipation within the soft starter during normal operation, leading to increased energy efficiency and reduced cooling requirements.

It also ensures maximum power is delivered to the motor when it's running at full speed, without the voltage drop associated with the soft starter's semiconductors.

What kind of motor protection is included in the 3RW5247-6AC14?

It features sophisticated electronic overload protection with adjustable trip classes. This protects the motor from thermal damage.

The starter also includes protection against phase unbalance and phase loss, critical for preventing motor damage in three-phase systems.

It can detect motor stalls and provides diagnostics for quick fault identification and mitigation, enhancing operational safety and reliability.

Can this soft starter be used in hazardous environments?

The standard enclosure for the 3RW5247-6AC14 is IP20, meaning it is protected against solid objects larger than 12.5mm but not against water ingress.

For hazardous environments with specific safety requirements, such as explosion protection, additional external enclosures or specialized certified equipment would be necessary.

Consult the product manual and local safety regulations to ensure appropriate application and any required environmental modifications or certifications.

What communication protocols does the 3RW5247-6AC14 support?

The base unit typically offers terminal connections for basic control and status signaling. This allows for straightforward integration into simpler automation setups.

Optional communication interface modules are available, commonly supporting industrial Ethernet protocols like PROFINET and PROFIBUS DP.

These modules enable seamless integration into advanced distributed control systems (DCS) or supervisory control and data acquisition (SCADA) networks for comprehensive data exchange.

How do I perform basic setup or programming for this soft starter?

Basic setup can often be performed directly via the soft starter's integrated keypad and display interface. This allows for initial parameterization.

More advanced configuration, including setting start/stop ramp times, current limits, and motor protection settings, can be done using Siemens' dedicated software tools accessible via the optional communication modules.

Refer to the specific user manual for detailed instructions on parameterization, including wiring examples and software connection guides for your chosen communication protocol.