Siemens 3RT6018-1BB41 Single Auxiliary High Current Power Contactor 24VDC 16A 3NO

The Siemens 3RT6018-1BB41 stands as a robust solution for high-current switching applications, offering a compact design with a 24VDC coil and a 16A rating. This single auxiliary contactor features three normally open (NO) contacts, making it ideal for direct control of motors, heating systems, and lighting circuits in industrial environments. Its key advantages lie in its reliable performance, energy-efficient operation, and straightforward integration into existing control panels.

Siemens 3RT6018-1BB41: Product Specifications

| Feature                 | Specification                               |

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

| Product Type            | Power Contactor                             |

| Model Number            | 3RT6018-1BB41                               |

| Coil Voltage            | 24VDC                                       |

| Rated Current (AC-3)    | 16A                                         |

| Number of Auxiliary Contacts | 1 NO (Normally Open)                        |

| Pole Configuration      | 3-Pole                                      |

| Enclosure Type          | Open                                        |

| Terminal Type           | Screw Terminals                             |

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

| Mounting Type           | DIN rail or screw mounting                  |

| Standards               | IEC 60947-4-1, IEC 60947-5-1, UL, CSA       |

| Dimensions (H x W x D)  | 70 mm x 45 mm x 88 mm                       |

Core Features & Market Positioning

The Siemens 3RT6018-1BB41 distinguishes itself through its compact form factor, a crucial consideration in space-constrained control cabinets. Its 24VDC coil design aligns with common control voltage standards, simplifying power supply requirements and enhancing safety. The inclusion of a single auxiliary contact provides essential feedback for control logic or interlocking circuits, offering versatility without unnecessary complexity. Siemens' reputation for industrial automation reliability underpins this component, positioning it as a dependable choice for critical switching tasks where longevity and performance are paramount. This contacTor is engineered for direct load switching, reducing the need for intermediary relays in many standard applications, thereby saving space and simplifying wiring.

Key Application Scenarios

This power contactor is exceptionally well-suited for controlling AC motors up to 5.5 kW (at 400V) in various industrial settings, including manufacturing plants, processing facilities, and building automation systems. Its 16A rating and 3 NO configuration make it a practical choice for managing heating elements in industrial ovens, controlling pumps in water treatment facilities, and switching lighting systems in large commercial spaces. The 24VDC coil is ideal for applications powered by low-voltage control systems, common in modern automation architectures. Its robust construction ensures reliable operation even in demanding environments, making it a preferred component for OEMs and system integrators focused on durability and efficiency.

Practical System Integration Guidance

Integrating the Siemens 3RT6018-1BB41 into a control system is straightforward. Power for the coil is supplied via the A1 and A2 terminals, with correct polarity crucial for DC operation. The main power circuit connects through the three primary poles (1, 2, 3 for input and 4, 5, 6 for output). The single auxiliary contact, typically a normally open (NO) type, can be wired to a control input for status feedback or interlock functions. Ensure that the connected load does not exceed the contacTor's rated capacity of 16A at the specified voltage. Proper wire sizing and terminal torque are essential for safe and reliable connections, preventing overheating and ensuring long-term performance. Always adhere to local electrical codes and safety standards during installation.

Operation and Risk Mitigation

The Siemens 3RT6018-1BB41 operates by energizing the 24VDC coil, which generates a magnetic field that pulls an armature, closing the main power contacts. De-energizing the coil releases the armature, and a spring returns the contacts to their normal position. To mitigate risks, always ensure the power supply is disconnected and LOTO (Lockout/Tagout) procedures are followed before performing any maintenance or wiring. Overloading the contacTor beyond its 16A rating can lead to overheating, premature wear, and potential fire hazards. Incorrect wiring, especially reversed polarity on the DC coil, will prevent operation and could damage control components. Regular visual inspection for signs of wear, discoloration, or damage to insulation is recommended.

Scalability & Long-Term Value

The Siemens 3RT6018-1BB41, as part of the broader Siemens industrial automation ecosystem, offers excellent long-term value. While this specific model is designed for direct control, it can be seamlessly integrated into larger PLC-based systems for sophisticated automation. Its compatibility with other Siemens components, such as overload relays and circuit breakers from the SIRIUS range, ensures easy expansion and system upgrades. For applications evolving towards Industry 4.0, the 3RT6018-1BB41 can serve as a foundational switching element within smart control cabinets, connected to digital platforms for remote monitoring and diagnostics, contributing to predictive maintenance strategies and enhanced operational efficiency.

Frequently Asked Questions

1. What is the maximum AC voltage rating for the Siemens 3RT6018-1BB41?

The Siemens 3RT6018-1BB41 is rated for 16A at AC-3 duty, typically for motor control.

The precise maximum AC voltage depends on the specific application and motor rating according to IEC standards.

Consult the full datasheet or Siemens technical support for detailed voltage application charts.

2. Can I use the Siemens 3RT6018-1BB41 for DC switching applications?

This contacTor is primarily designed for AC loads based on its AC-3 rating.

Using it for DC loads requires careful calculation and derating due to arc suppression differences.

Consult Siemens' specific guidelines for DC switching applications with this contacTor model.

3. What is the function of the single auxiliary contact on the 3RT6018-1BB41?

The auxiliary contact provides a signal for control circuits, not for power switching.

It can be wired as normally open (NO) or normally closed (NC) depending on the configuration needed.

This contact is often used for status feedback or interlocking with other control devices.

4. How do I wire the 24VDC coil for the Siemens 3RT6018-1BB41?

Connect the positive (+) terminal of the 24VDC supply to A1 and the negative (-) terminal to A2.

Ensure the power supply is stable and within the specified tolerance for the 24VDC coil.

Reversing polarity on a DC coil will prevent it from energizing and can damage control circuitry.

5. What are the dimensions of the Siemens 3RT6018-1BB41 contacTor?

The contacTor has a compact design suitable for DIN rail mounting or direct screw fixing.

Its approximate dimensions are 70mm in height, 45mm in width, and 88mm in depth.

These compact dimensions aid in space-saving within control panels and enclosures.

6. What type of overload protection is recommended for this contacTor?

External overload relays, such as Siemens 3RU series, are typically used for motor protection.

The overload relay should be sized appropriately for the motor current and the contacTor's rating.

Ensure the overload relay is correctly coordinated with the contacTor for safe operation.

7. Is the Siemens 3RT6018-1BB41 suitable for frequent switching cycles?

Yes, Siemens contacTors are built for industrial durability and reliable operation over many cycles.

The lifespan depends on the switching frequency, load, and environmental conditions.

Proper application within rated parameters ensures optimal service life.

8. What is the significance of the "3NO" designation?

"3NO" signifies that the contacTor has three main poles, each normally open.

When the coil is energized, all three poles close simultaneously to switch the load.

This configuration is standard for controlling three-phase AC motors.

9. Can this contacTor be used in hazardous environments?

The standard 3RT6018-1BB41 is not intrinsically safe or explosion-proof.

For hazardous locations, specific ATEX or IECEx certified equipment is required.

Always verify the suitability of any component for hazardous area classifications.

10. Where can I find the full technical datasheet for the Siemens 3RT6018-1BB41?

The most comprehensive information is available on the official Siemens Industry Online Support (SIOS) portal.

You can also find datasheets from authorized Siemens distributors and industrial automation suppliers.

Searching for "Siemens 3RT6018-1BB41 datasheet" will yield multiple reliable sources.