Siemens 3RT1056-6AF36 SIRIUS AC Contactor 110-127VAC/DC 185A 3NO

The Siemens 3RT1056-6AF36 SIRIUS AC Contactor is a robust and reliable industrial switching device designed for demanding applications. With a significant 185A current rating and 3 normally open (NO) poles, this 110-127VAC/DC operated contactor offers exceptional performance for motor control, power distribution, and switching of heavy loads. Its SIRIUS line benefits from Siemens' extensive experience in industrial automation, ensuring high operational safety, long service life, and seamless integration into various control systems.

Product Specifications

| Feature                  | Specification                                 |

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

| Product Type             | SIRIUS AC Contactor                           |

| Manufacturer             | Siemens                                       |

| Model Number             | 3RT1056-6AF36                                 |

| Coil Voltage             | 110-127 VAC/DC                                |

| Conventional Thermal Current (Ith) | 185 A                                         |

| Number of NO Poles       | 3                                             |

| Number of NC Poles       | 0                                             |

| Auxiliary Contacts       | Typically 1 NO + 1 NC (often sold separately or integrated into specific variants) |

| Control Circuit Voltage  | 110-127 VAC/DC                                |

| Mounting Type            | Screw terminal or rail mount                  |

| Protection Rating        | IP20                                          |

| Dimensions (H x W x D)   | Varies by mounting, but generally compact for its rating |

| Standards Compliance     | IEC, UL, CSA                                  |

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

Core Features & Market Positioning

The Siemens 3RT1056-6AF36 distinguishes itself through its high switching capacity and versatile coil voltage, accommodating both AC and DC control signals within a common range. This flexibility simplifies inventory and application design for global projects. The SIRIUS 3RT line is positioned as a premium solution, emphasizing reliability, safety, and longevity in harsh industrial environments. Siemens' commitment to quality ensures that these contactors meet stringent international standards, offering a competitive edge over less robust alternatives, particularly in sectors demanding continuous operation and minimized downtime. Its robust construction is engineered for high electrical endurance, making it a preferred choice for applications involving frequent switching cycles.

Key Application Scenarios

This Siemens 3RT1056-6AF36 contactor is ideally suited for controlling and switching heavy-duty loads, such as large industrial motors, capacitor banks for power factor correction, and high-power lighting systems. Its 185A rating makes it a powerful component in main power distribution panels, pump control systems, and HVAC equipment where robust switching capabilities are paramount. Industries such as manufacturing, material handling, water treatment, and heavy machinery rely on contactors like this for their operational integrity. Furthermore, its dual AC/DC coil voltage simplifies control circuit design, making it applicable across diverse automation architectures where different control signal types are present.

Practical System Integration Guidance

Integrating the Siemens 3RT1056-6AF36 into an industrial control system requires careful attention to wiring and safety protocols. For motor control applications, it's typically used in conjunction with overload relays, such as Siemens 3RU or 3RB series, to provide comprehensive motor protection against overcurrent and phase loss. The main power terminals should be connected to the load and supply circuits, ensuring proper torque is applied to the screw terminals to maintain secure connections. The 110-127VAC/DC control coil can be wired directly from a suitable control power transformer or DC power supply, with a dedicated fuse or circuit breaker for the control circuit. Proper grounding of the contactor and associated equipment is critical for safety. When replacing existing contactors, verifying the coil voltage and current rating compatibility is essential.

Operation and Risk Mitigation

Safe operation of the Siemens 3RT1056-6AF36 hinges on adherence to electrical codes and manufacturer guidelines. Overloading the contactor beyond its 185A rating can lead to premature failure, overheating, and potential fire hazards. Ensure the control circuit voltage precisely matches the specified 110-127VAC/DC range to prevent coil damage or failure to operate. Regularly inspect terminals for signs of corrosion or loosening, and perform periodic functional tests to confirm proper actuation and contact integrity. In case of erratic operation or failure to switch, disconnect power immediately and consult the SIRIUS system documentation. Faulty contactors can cause unexpected machine startup or failure to stop, posing significant safety risks; therefore, a proactive maintenance schedule is crucial for risk mitigation.

Scalability & Long-Term Value

The SIRIUS 3RT1056-6AF36 is part of a broad ecosystem of Siemens industrial components, offering excellent scalability and long-term value. It is designed for compatibility with other SIRIUS devices, including overload relays, auxiliary switches, and communication modules, allowing for the expansion and enhancement of control systems. For advanced integration, it can be incorporated into distributed I/O systems or networked control platforms, supporting the evolution towards Industrial Internet of Things (IIoT) and Industry 4.0 initiatives. This ensures that investments in Siemens contactors remain relevant and can be leveraged for future automation upgrades, providing a reliable foundation for smart manufacturing environments.

Frequently Asked Questions

Q1: What is the maximum voltage this Siemens contactor can handle?

This Siemens 3RT1056-6AF36 contactor is rated for 185 Amps. It is designed to switch heavy electrical loads effectively.

The coil operates on 110-127 VAC or DC. This offers flexibility in control system design.

Always ensure your application's voltage and current requirements are within these specified limits for safety.

Q2: How do I wire the coil for the Siemens 3RT1056-6AF36?

Connect your 110-127V AC or DC control power source to the coil terminals. Observe polarity if using DC.

Ensure the control circuit is properly fused or protected by a breaker for safety. Use appropriate wire gauges.

Consult the Siemens wiring diagrams for precise connections and any necessary auxiliary components.

Q3: Can this contactor be used with DC motors?

Yes, the 110-127V AC/DC coil allows operation with DC control signals. The contactor itself is primarily for AC load switching.

For DC motor loads, you would need a DC-rated contactor or ensure the motor's start/run characteristics are compatible.

Always verify the specific motor load's current and voltage requirements against the contactor's AC rating.

Q4: What is the difference between NO and NC contacts?

NO (Normally Open) contacts are open when the coil is de-energized and close when energized. This contactor has 3 NO poles.

NC (Normally Closed) contacts are closed when the coil is de-energized and open when energized. This model has no NC poles built-in.

These contacts are used for various control logic and signaling functions within the automation system.

Q5: How do I protect the motor controlled by this contactor?

Pair the Siemens 3RT1056-6AF36 with a compatible Siemens overload relay, like the 3RU or 3RB series.

The overload relay provides essential protection against overcurrent and phase failure. Set it to the motor's full load amps (FLA).

Ensure proper wiring between the contactor and the overload relay for effective coordinated protection.

Q6: Is this contactor suitable for frequent switching applications?

Yes, SIRIUS contactors are designed for high electrical endurance and reliability. They handle frequent switching well.

The 3RT1056-6AF36 is built to withstand demanding duty cycles common in industrial settings.

Regular maintenance and proper load matching will maximize its operational lifespan.

Q7: What are the typical applications for the Siemens 3RT1056-6AF36?

This 185A contactor is ideal for switching heavy loads like large industrial motors, pumps, and HVAC systems.

It's commonly used in main power distribution and control panels across various industries.

Applications also include capacitor bank switching and high-power lighting control circuits.

Q8: Can I add auxiliary contacts to this contactor?

Yes, auxiliary contact blocks (front or side-mounted) can often be added. Check for compatibility with this specific model.

These provide additional contacts for control, signaling, or interlocking purposes.

Refer to Siemens documentation for approved auxiliary contact modules for the 3RT1056 series.

Q9: What safety precautions should I take when installing this contactor?

Always disconnect main power before installation or maintenance. Follow all local electrical codes and safety standards.

Ensure proper grounding of the enclosure and the contactor itself. Use appropriate PPE.

Verify the coil voltage and load current ratings are correctly matched to your application.

Q10: Where can I find a wiring diagram for this Siemens contactor?

Siemens provides detailed wiring diagrams in the product's technical documentation and on their website.

You can often find these diagrams on the product's datasheet or within the SIRIUS system catalog.

Consulting the official Siemens resources ensures accurate and safe installation.