Siemens 3RT2027-2KF40 AC Contactor with Surge Suppressor 110VDC 32A 3NO

The Siemens 3RT2027-2KF40 AC Contactor with Surge Suppressor is a robust, reliable component designed for demanding industrial applications. This 3-pole contactor boasts a 32A rating at AC-3 duty and a 15kW power rating at 400V, ensuring efficient operation for motor control and power switching. Its 110V DC coil voltage provides compatibility with a wide range of control systems, while the integrated varistor offers essential surge suppression. The inclusion of 1 normally open (NO) and 1 normally closed (NC) auxiliary contacts facilitates complex control logic and status feedback. Designed for ease of integration, it features spring-type terminals for secure and fast connections.

Product Specifications

| Specification                      | Value                                                                   |

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

| Product Number                     | 3RT2027-2KF40                                                           |

| Brand                              | Siemens                                                                 |

| Series                             | SIRIUS 3RT2                                                             |

| Frame Size                         | S0                                                                      |

| Number of Poles                    | 3                                                                       |

| Rated Operational Current (AC-3)   | 32 A (at 400V)                                                          |

| Rated Operational Power (AC-3)     | 15 kW (at 400V)                                                         |

| Coil Voltage                       | 110 V DC                                                                |

| Auxiliary Contacts                 | 1 NO + 1 NC                                                             |

| Terminal Type                      | Spring-type terminals                                                   |

| Surge Suppression                  | Integrated Varistor                                                     |

| Insulation Voltage (Ui)            | 690 V                                                                   |

| Rated Impulse Voltage (Uimp)       | 6 kV                                                                    |

| Operating Temperature Range        | -25 °C to +70 °C                                                        |

| Mechanical Service Life            | 10,000,000 operations                                                   |

| Mounting                           | DIN rail or surface mounting                                            |

| Standards                          | IEC 60947-1, IEC 60947-4-1                                              |

Core Features & Market Positioning

The Siemens 3RT2027-2KF40 stands out in the industrial control market due to its combination of a compact S0 frame size with significant power handling capabilities. Its primary advantage lies in its robust design, suitable for continuous industrial operation, and its direct compatibility with electronic controllers, making it a preferred choice for modern automation systems. The integrated surge suppressor is a key differentiator, offering built-in protection against voltage transients that can damage control circuitry, thereby enhancing system reliability and reducing maintenance needs. This product is positioned as a high-reliability, cost-effective solution for motor control and switching applications where dependability is paramount.

Key Application Scenarios

This Siemens 3RT2027-2KF40 AC contactor is extensively utilized across various industrial sectors for controlling and switching electric motors, pumps, fans, and other inductive loads. Its suitability for Direct On-Line (DOL) starting makes it a common component in basic motor control circuits. The 110V DC control voltage aligns well with applications using PLC (Programmable Logic Controller) outputs, facilitating seamless integration into automated systems. Furthermore, its robust construction and compliance with IEC standards render it suitable for demanding environments, including those found in manufacturing plants, water treatment facilities, and HVAC systems. It is also noted for its application in railway systems due to its reliable performance characteristics.

Practical System Integration Guidance

Integrating the Siemens 3RT2027-2KF40 into an industrial control panel is straightforward, thanks to its spring-type terminals which ensure fast, reliable, and vibration-proof connections without requiring specialized tools. The contactor is designed for both DIN rail and surface mounting, offering flexibility in panel design. For control circuits, the 110V DC coil is directly compatible with standard PLC digital outputs. The presence of 1 NO and 1 NC auxiliary contacts allows for immediate implementation of interlocking logic, overcurrent trip signaling, or status indication. It is important to note that this specific model (3RT2027-2KF40) is not expandable with additional auxiliary switches.

Operation and Risk Mitigation

Proper operation of the Siemens 3RT2027-2KF40 requires adherence to its specified electrical ratings and environmental conditions. The integrated varistor provides a degree of protection against voltage spikes, but it is crucial to ensure that the control voltage remains within the specified 0.7-1.25 * Uc range for the 110V DC coil. Overloading the contactor beyond its AC-3 rating of 32A can lead to premature failure of the contacts and internal components. In troubleshooting scenarios, common issues may involve a failure to energize (check coil voltage and wiring) or a failure to open/close (inspect contacts for welding or debris). While specific error codes are not typically associated with electromechanical contactors, a careful visual inspection and continuity testing of the contacts and coil are standard diagnostic procedures. Adherence to safety protocols during installation and maintenance, such as de-energizing the circuit, is paramount.

Scalability & Long-Term Value

The Siemens 3RT2027-2KF40 is part of the comprehensive SIRIUS modular system, offering excellent compatibility with other Siemens control and protection devices. While this particular model does not support auxiliary switch expansion, its robust design and high mechanical service life of 10 million operations ensure long-term value and reliability. Its direct connection capability to electronic controllers aligns with trends in industrial automation and the Industrial Internet of Things (IIoT), allowing for straightforward integration into networked control systems where data acquisition and remote monitoring are key. Compatibility with other SIRIUS components, such as overload relays and circuit breakers, facilitates the creation of complete, coordinated motor feeder solutions.

Frequently Asked Questions (FAQs)

Q1: What is the maximum AC power the Siemens 3RT2027-2KF40 can switch?

The Siemens 3RT2027-2KF40 is rated for 15 kW at AC-3 duty and 400V. This rating is crucial for motor control applications.

It can handle up to 32A at AC-3 for motor loads. This ensures reliable switching of motor currents.

This contactor is also rated for AC-1 duty at 50A for resistive loads. This broadens its application scope beyond motor control.

Q2: What type of coil voltage does the Siemens 3RT2027-2KF40 use?

This contactor operates with a 110V DC coil voltage. This is a common voltage for control circuits in industrial settings.

The coil voltage range for reliable operation is typically 0.7 to 1.25 times the rated voltage. This ensures consistent performance.

This DC voltage makes it highly compatible with PLC outputs and other low-voltage DC control systems. Seamless integration is a key benefit.

Q3: Does the Siemens 3RT2027-2KF40 have surge suppression?

Yes, the Siemens 3RT2027-2KF40 features an integrated varistor for surge suppression. This protects against voltage spikes.

The integrated varistor helps to absorb transient overvoltages, enhancing the lifespan of the contactor and connected equipment. It offers built-in protection.

This built-in protection simplifies wiring and reduces the need for external suppression components, saving space and installation time. It adds value and convenience.

Q4: Can additional auxiliary contacts be added to the Siemens 3RT2027-2KF40?

No, the Siemens 3RT2027-2KF40 is designed without the capability to add auxiliary switches. It comes with integrated 1NO+1NC contacts.

The fixed 1 NO and 1 NC auxiliary contacts are suitable for many standard control and signaling functions. They offer basic flexibility.

For applications requiring more auxiliary contacts, alternative Siemens contactors from the SIRIUS range may be necessary. Expansion options vary by model.

Q5: What are the advantages of using spring-type terminals on this contactor?

Spring-type terminals offer fast and secure connections without the need for screwdrivers. This speeds up installation.

These terminals are vibration-proof, ensuring reliable electrical contact even in harsh industrial environments. They enhance durability.

Spring terminals often require less maintenance than screw terminals, as they maintain consistent clamping force over time. This reduces long-term upkeep.

Q6: Is the Siemens 3RT2027-2KF40 suitable for PLC outputs?

Yes, its 110V DC coil voltage is directly compatible with many PLC digital outputs. This simplifies integration into automated systems.

PLCs can readily provide the necessary 110V DC signal to energize the coil and activate the contactor. This ensures seamless operation.

This direct compatibility reduces the need for intermediate relays, streamlining control panel design and reducing costs. It offers an efficient solution.

Q7: What is the mechanical service life of the Siemens 3RT2027-2KF40?

The contactor has a mechanical service life of up to 10,000,000 operations. This indicates high durability.

This long mechanical life ensures reliable performance over many switching cycles. It is built for longevity.

This extended service life contributes to a lower total cost of ownership by reducing the frequency of component replacement. It offers long-term value.

Q8: What standards does the Siemens 3RT2027-2KF40 comply with?

The Siemens 3RT2027-2KF40 complies with key international standards, including IEC 60947-1 and IEC 60947-4-1. These are crucial for industrial control gear.

Compliance with these standards ensures that the contactor meets rigorous safety and performance requirements for worldwide use. It guarantees quality.

Adherence to these standards facilitates integration into systems designed to meet global regulatory requirements. It simplifies international deployment.

Q9: What is the frame size of this Siemens contactor?

This Siemens contactor is designated as frame size S0. This is a standard size for many industrial applications.

Frame size S0 indicates a specific physical dimension and power handling capacity within the SIRIUS 3RT family. It defines its footprint.

The S0 size offers a good balance between compact dimensions and the 32A/15kW power rating, making it versatile. It is well-suited for many panel designs.

Q10: Where can I find the datasheet for the Siemens 3RT2027-2KF40?

Datasheets for the Siemens 3RT2027-2KF40 are available on the Siemens SiePortal website and through major industrial component distributors like RS Components. These provide detailed technical specifications.

You can also find product data sheets linked on various industrial automation supplier websites. Searching the product number will often yield these documents.

These datasheets contain comprehensive information including electrical ratings, dimensions, environmental data, and compliance certificates for the 3RT2027-2KF40. They are essential for design and installation.