Siemens 3RT6025-1KF40 Protected Safety Control Contactor 110VDC 17A 3NO

The Siemens 3RT6025-1KF40 Protected Safety Control Contactor, a vital component for industrial automation, offers robust safety control with a 110VDC coil and a 17A rating, featuring 3 normally open (NO) contacts. This contactor is engineered for reliable switching in demanding environments, ensuring operational continuity and personnel safety. Its core advantages lie in its integrated safety functions, compact design, and high switching capacity, making it a preferred choice for machine control and safety circuits in various industrial sectors.

Product Specifications

| Feature                     | Specification                                  |

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

| Product Type                | Protected Safety Control Contactor             |

| Model Number                | 3RT6025-1KF40                                  |

| Coil Voltage                | 110V DC                                        |

| Rated Operational Current   | 17 A                                           |

| Number of NO Contacts       | 3                                              |

| Number of NC Contacts       | 0                                              |

| Auxiliary Contacts          | 1 NO + 1 NC (integrated in some versions)      |

| Mounting Type               | Rail mount (35 mm DIN rail)                    |

| Protection Class            | IP20 (or as per specific enclosure)            |

| Ambient Operating Temperature | -25 to +60 °C                                  |

| Terminal Type               | Screw terminals                                |

| Standards                   | IEC 60947-4-1, IEC 60947-5-1, EN 60204-1, VDE0113 |

| Safety Integrity Level (SIL) | SIL 2 (when used in safety-related applications) |

Core Features & Market Positioning

The Siemens 3RT6025-1KF40 distinguishes itself through its inherent safety-oriented design, aligning with stringent industrial safety standards like EN 60204-1. Its primary function is to reliably disconnect hazardous machinery in emergency situations, providing a crucial layer of protection. The contactor's robust construction ensures long operational life and consistent performance, even under frequent switching cycles. It is positioned as a reliable, high-quality component for safety circuits, offering a compelling alternative to standard contactors where functional safety is paramount. Competitively, it provides a cost-effective solution for achieving safety integrity levels (SIL) up to SIL 2 when integrated correctly into a safety system.

Key Application Scenarios

This Siemens contactor is extensively employed in safety-related applications across diverse industries. Common use cases include emergency stop circuits, where it ensures rapid and reliable power disconnection to machinery upon activation of an E-stop button. It is also integral to safety gates and light curtains, interrupting machine operation when protective barriers are breached. Industries such as machine building, automotive manufacturing, and process automation frequently specify the 3RT6025-1KF40 for applications requiring safe state transitions and reliable fault detection. Its 110VDC coil voltage makes it suitable for systems utilizing DC power supplies.

Practical System Integration Guidance

Integrating the Siemens 3RT6025-1KF40 into control systems is straightforward, leveraging standard industrial practices. Mounting is typically achieved via a 35mm DIN rail, ensuring quick and secure installation. Wiring involves connecting the control circuit to the coil terminals (A1/A2) for activation and deactivation. The main power contacts are wired in series with the load that requires safe switching. For safety circuits, it's crucial to connect the contactor in a manner that ensures fail-safe operation, often in conjunction with safety relays or safety PLCs. Always refer to the official Siemens documentation for precise wiring diagrams and safety recommendations, particularly when achieving specific SIL ratings.

Operation and Risk Mitigation

The 3RT6025-1KF40 operates by energizing its 110VDC coil, which magnetically actuates the contacts to close the 3 NO circuits, allowing power to flow to the connected loads. When the coil is de-energized, the contacts spring back to their default (open) state, interrupting the power flow. Risk mitigation is inherent in its design; the use of positively driven contacts ensures that if a contact weld occurs, the normally closed (NC) auxiliary contacts (if present) will not mirror the state of the main contacts, providing a diagnostic capability. In safety applications, failure to open when de-energized is a critical fault. Proper wiring and periodic testing are essential to mitigate risks and ensure the contator performs its safety function as intended.

Scalability & Long-Term Value

The Siemens 3RT6025-1KF40 offers significant long-term value through its compatibility with Siemens' broader automation portfolio, including SIMATIC PLCs and HMI panels. This allows for seamless integration into larger, more complex industrial control systems and digital transformation initiatives. While the contactor itself is a discrete component, its integration into modular control cabinets allows for easy replacement or expansion of safety circuits. Its robust design ensures longevity, reducing the total cost of ownership through reduced maintenance and fewer unexpected failures. For IIoT integration, it can be monitored via auxiliary contacts wired to digital input modules, providing status feedback to higher-level systems.

Frequently Asked Questions

What is the primary function of the Siemens 3RT6025-1KF40?

The Siemens 3RT6025-1KF40 is designed as a protected safety control contactor. Its main purpose is to reliably switch electrical loads, particularly in safety-related applications. It ensures that hazardous parts of machinery can be safely disconnected from the power supply when needed.

It plays a crucial role in emergency stop circuits and other safety interlocks. The contactor's design focuses on dependable operation under fault conditions, contributing to overall machine safety and operator protection.

This component is essential for compliance with industrial safety standards like EN 60204-1, ensuring machines operate within defined safety parameters.

How is the Siemens 3RT6025-1KF40 installed in a control panel?

Installation is typically done on a standard 35mm DIN rail. This mounting method is common in industrial control panels, allowing for quick and secure attachment of various components.

The contactor's compact size and straightforward mounting mechanism simplify cabinet assembly and maintenance. Proper alignment and secure fastening are key for reliable electrical connections.

Ensure adequate ventilation around the contactor to maintain optimal operating temperatures, especially in enclosed control cabinets with higher ambient heat.

What are the key technical specifications of this contactor?

This contactor operates with a 110V DC coil voltage for control. It is rated for an operational current of 17 Amperes.

It features three normally open (NO) main contacts for switching the load circuits. Some versions may include integrated auxiliary contacts for signaling purposes.

The device is designed for industrial environments, typically with an IP20 protection rating and a wide operating temperature range, ensuring robust performance.

Can the Siemens 3RT6025-1KF40 be used in standard motor control circuits?

While it can switch loads, its primary design intent is for safety-related applications. It is not typically the first choice for standard, non-safety motor starting where simpler contactors might suffice.

Using it in safety circuits ensures that if an emergency stop is triggered, the motor power is reliably interrupted. This is a key differentiator from basic control contactors.

For standard motor control without safety requirements, other Siemens contactor series might offer more specific features or cost efficiencies. Always assess the safety integrity needs.

What does "Protected Safety Control Contactor" signify?

It signifies that the contactor is specifically designed and certified for use in functional safety applications. These applications require a higher degree of reliability and predictability of failure.

"Protected" implies built-in features that enhance safety, such as positively driven contacts. This feature helps in diagnostics and ensures that the state of auxiliary contacts reflects the main contacts accurately.

This designation means it adheres to specific safety standards (e.g., IEC 61508, ISO 13849) and can contribute to achieving defined Safety Integrity Levels (SIL) or Performance Levels (PL).

What is the role of the 110V DC coil voltage?

The 110V DC coil voltage specifies the electrical potential required to energize the contactor's electromagnet. This energy causes the contacts to change state (close for NO, open for NC).

This DC voltage rating is important for system designers to match with the available power supply within the control system. It ensures proper activation of the contactor's switching mechanism.

Systems designed with 110V DC power distribution are common in certain industrial automation setups, making this contactor a direct fit for such environments.

How does the Siemens 3RT6025-1KF40 contribute to machine safety?

It contributes by providing a reliable means to disconnect power from hazardous machinery. In emergency situations, its rapid and dependable switching action minimizes potential harm.

Its design incorporates features that ensure it fails in a safe state, meaning power is interrupted when the control signal is lost or an internal fault occurs. This is critical for safety functions.

By meeting stringent safety standards, it allows machine builders to design systems that comply with regulatory requirements and protect personnel effectively.

Are there specific wiring considerations for safety applications?

Yes, wiring in safety applications is critical and follows strict guidelines to ensure fail-safe operation. Always consult the product's technical documentation and relevant safety standards.

For safety functions, the contactor must be integrated into a safety circuit, often involving safety relays or safety PLCs. The wiring must ensure that the contactor opens when commanded or in case of a fault.

Properly grounding and shielding of control wires are also important to prevent spurious signals or electromagnetic interference that could compromise safety.

What are the benefits of using this specific Siemens contactor over a standard one?

The primary benefit is its enhanced reliability and suitability for safety-critical functions. It is designed to meet higher safety integrity requirements.

It often incorporates features like positively driven contacts, which provide diagnostic capabilities that standard contactors lack, improving fault detection.

Using a safety-rated contactor simplifies the process of achieving compliance with safety standards and reduces the risk associated with machine operation.

What type of loads can the Siemens 3RT6025-1KF40 reliably switch?

With a 17A rating, it can switch various types of industrial loads, including motor circuits, lighting, heating elements, and inductive loads. It's crucial to consider power factor and inrush current for specific applications.

For inductive loads (like motors), it's advisable to use arc suppression devices or select contactors with appropriate ratings to handle the surge current upon switching.

Always verify that the load characteristics fall within the specified operational current and voltage limits of the 3RT6025-1KF40 to ensure safe and reliable operation.