Siemens 3RT2027-1AK60 High Capacity AC Contactor 110VAC 32A 3NO

The Siemens 3RT2027-1AK60 stands as a robust High Capacity AC Contactor, engineered for demanding industrial applications. This 110VAC contactor boasts a significant 32A rating and a configuration of 3 Normally Open (NO) poles, making it an ideal choice for reliable power switching. Its core advantages lie in its compact design, exceptional durability, and straightforward integration into various control systems. Key technical parameters include a standard coil voltage of 110VAC, a rated operational current of 32A at AC-3 utilization category, and a 3NO pole arrangement suitable for motor control and power distribution.

Product Specifications

| Feature                 | Specification                      |

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

| Product Type            | Power Contactor                    |

| Manufacturer            | Siemens                              |

| Series                  | 3RT2 SIRIUS                        |

| Model Number            | 3RT2027-1AK60                      |

| Rated operational power | 15 kW (at AC-3, 400 V)             |

| Rated operational current | 32 A (at AC-3, 400 V)              |

| Number of NO poles      | 3                                  |

| Coil voltage            | 110 VAC                            |

| Auxiliary contacts      | 1 NO + 1 NC (integrated)           |

| Mounting type           | Rail or Screw Mount                |

| Protection rating       | IP20                               |

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

| Dimensions (H x W x D)  | 96 mm x 45 mm x 107 mm             |

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

Core Features & Market Positioning

The Siemens 3RT2027-1AK60 distinguishes itself within the industrial control market through its inherent reliability and Siemens' reputation for quality engineering. Its compact 45mm width is a significant advantage, allowing for space-saving installations in control cabinets, a critical factor in modern panel design. The SIRIUS innovation ensures consistent performance across a wide temperature range, from -25°C to +60°C, and features robust terminal connections that resist loosening over time, minimizing maintenance needs. This combination of space efficiency, operational stability, and long-term dependability positions it as a superior choice for applications where downtime is unacceptable.

Key Application Scenarios

This high-capacity AC contactor is exceptionally versatile, finding primary use in motor control circuits for starting, stopping, and reversing three-phase motors within its power rating. It is frequently specified for applications such as pump control, fan systems, conveyor belts, and general power distribution in manufacturing plants, building automation, and HVAC systems. The 32A rating makes it suitable for medium-sized industrial machinery, providing reliable switching for loads up to 15 kW at 400V AC-3.

Practical System Integration Guidance

Integrating the Siemens 3RT2027-1AK60 is facilitated by its standard mounting options, allowing for direct attachment to a 35mm DIN rail or screw mounting for fixed installations. Wiring is straightforward; power terminals are clearly marked for incoming and outgoing power, while the coil terminals (A1 and A2) are designed for direct connection to the 110VAC control circuit. The integrated auxiliary contacts (1 NO + 1 NC) can be easily wired into the control logic for status feedback or interlocks. For motor control, it is typically used in conjunction with an overload relay (e.g., Siemens 3RU series) for comprehensive motor protection, ensuring safe and efficient operation.

Operation and Risk Mitigation

Safe operation of the Siemens 3RT2027-1AK60 relies on adherence to electrical codes and proper installation practices. Ensure the coil voltage precisely matches the control supply (110VAC) to prevent damage. Always disconnect power before performing any wiring or maintenance. The contactor is designed for frequent switching operations but should be sized correctly for the load to avoid premature wear. In case of failure to switch, common causes include incorrect wiring, coil voltage issues, or mechanical obstruction. Troubleshooting typically involves checking control voltage, verifying wiring integrity, and inspecting for physical damage. The IP20 protection rating signifies it is suitable for indoor use in protected environments, not exposed to dust or moisture.

Scalability & Long-Term Value

The Siemens 3RT2027-1AK60 is part of the broader SIRIUS innovation platform, offering excellent compatibility with other Siemens control and automation components. This modularity allows for seamless integration into larger control systems, including those employing Programmable Logic Controllers (PLCs) and Human-Machine Interfaces (HMIs). Its robust construction ensures a long operational lifespan, reducing the total cost of ownership. For future upgrades or expansion, the SIRIUS system provides a clear pathway, enabling users to easily add more contactors, overload relays, or advanced communication modules as system requirements evolve, supporting the move towards Industry 4.0 and IIoT integration.

Frequently Asked Questions (FAQs)

1. What is the correct coil voltage for the Siemens 3RT2027-1AK60?

The Siemens 3RT2027-1AK60 is designed with a specific coil voltage requirement of 110VAC. Using any other voltage can lead to malfunction or permanent damage to the contactor. Always verify the control power source matches this specification before wiring.

Ensuring the correct coil voltage is critical for the operational integrity and longevity of the 3RT2027-1AK60. Incorrect voltage can result in the contactor failing to energize or to hold its state properly. Proper electrical design and installation practices will guarantee the correct voltage is supplied to the coil terminals (A1/A2).

Referencing the product manual or the label on the contactor itself will confirm the 110VAC requirement. This ensures that electricians and maintenance personnel select the appropriate transformer or power supply for the control circuit.

2. Can the Siemens 3RT2027-1AK60 be used for DC loads?

No, the Siemens 3RT2027-1AK60 is specifically an AC contactor and is not designed for direct use with DC loads. AC contactors operate on different principles than DC contactors. Using it for DC loads can lead to contact welding and unsafe operation.

For DC applications, a dedicated DC contactor with appropriate arc suppression is necessary. Siemens offers a range of DC contactors within the SIRIUS innovation line that are built for these specific requirements. Always consult the product datasheets to ensure you are selecting the correct type of contactor for your specific load.

If you have a mixed AC/DC system, it is imperative to use separate contactors rated for each type of power. This segregation prevents potential hazards and ensures the reliable performance of your control system components.

3. What is the maximum power this contactor can switch?

The Siemens 3RT2027-1AK60 has a rated operational current of 32A at AC-3 utilization category, which translates to a maximum switched power of 15 kW at 400V. This rating is crucial for motor control applications where inrush current is higher.

When applying this contactor, it is vital to consider the motor's full load current and its starting characteristics. The AC-3 rating implies switching three-phase induction motors where the motor is started directly online and then runs.

For applications with frequent starts, very high starting torques, or loads other than standard motors, a derating or a different contactor class might be necessary. Always refer to the technical documentation for specific application guidance.

4. How do I wire the Siemens 3RT2027-1AK60 for motor control?

For standard three-phase motor control, wire the incoming power (L1, L2, L3) to the main power terminals (e.g., 1, 3, 5). Then, connect the motor leads (T1, T2, T3) to the outgoing power terminals (e.g., 2, 4, 6). The coil is controlled by the 110VAC supply connected to terminals A1 and A2.

It is highly recommended to pair this contactor with a Siemens overload relay (e.g., 3RU series) for motor protection. The overload relay typically mounts directly below the contactor and its control circuit is wired in series with the contactor coil, allowing it to trip and open the control circuit if an overload condition is detected.

The integrated auxiliary contacts (1 NO and 1 NC) can be used for signaling purposes. The NO contact can be wired in parallel with the control contactor coil's energizing circuit for self-holding, or used in an alarm circuit. The NC contact is often used in safety interlocks or to signal an 'off' status.

5. What does the "3NO" designation mean?

The "3NO" in the Siemens 3RT2027-1AK60 designation signifies that the contactor has three main poles, and each of these poles is configured as a Normally Open (NO) contact. This means that when the contactor coil is de-energized, these three contacts are open, preventing current flow.

When the 110VAC coil is energized, it operates an internal mechanism that closes all three NO contacts simultaneously. This allows current to flow through the main power circuit, typically for switching a three-phase motor or other three-phase load.

The configuration of 3NO poles is standard for controlling three-phase motors directly across the line. If your application requires Normally Closed (NC) contacts, additional auxiliary contact blocks can often be attached to the front or side of the contactor.

6. Is this contactor suitable for high inrush current applications?

The Siemens 3RT2027-1AK60, rated at AC-3, is designed to handle the typical inrush current of standard induction motors. The AC-3 utilization category accounts for starting motors where there is a high initial current.

However, for applications with exceptionally high inrush currents, such as heavily loaded motors, motors with soft starters, or variable frequency drives (VFDs) that may have higher current demands during certain operational modes, a specific analysis is required. In such cases, a contactor with a higher AC-3 rating or a specialized application contactor might be more appropriate.

Always consult the detailed technical data and consider the specific motor characteristics and operational duty cycle. Oversizing the contactor slightly for very demanding applications can enhance reliability and extend its service life.

7. What are the dimensions of the Siemens 3RT2027-1AK60?

The Siemens 3RT2027-1AK60 has compact dimensions of approximately 96 mm in height, 45 mm in width, and 107 mm in depth. This narrow width of 45mm is a significant advantage for space-constrained control panel designs.

These dimensions allow for a high power density, meaning a substantial current handling capability is packed into a relatively small footprint. This is crucial for modern industrial automation where cabinet space is often at a premium.

When planning installations, ensure sufficient clearance around the contactor for ventilation and accessibility, especially when combined with other components like overload relays or terminal blocks.

8. Does this contactor come with integrated overload protection?

No, the Siemens 3RT2027-1AK60 itself does not include integrated overload protection. It is a power contactor designed to switch the power circuit, while overload protection is typically provided by a separate overload relay.

Siemens offers compatible overload relays, such as those in the 3RU series, which are designed to mount directly onto the 3RT2027-1AK60. These relays monitor the motor current and will trip to de-energize the contactor in case of an overcurrent condition, protecting the motor from damage.

It is a standard and critical practice in motor control systems to always use a contactor in conjunction with an appropriately sized overload relay to ensure comprehensive protection for both the motor and the electrical system.

9. What is the operating temperature range for this contactor?

The Siemens 3RT2027-1AK60 is rated to operate reliably within an ambient temperature range of -25°C to +60°C. This broad range makes it suitable for a variety of industrial environments, from cold storage to moderately heated areas.

Maintaining performance across this wide temperature spectrum is crucial for industrial equipment. Deviations outside this range could affect the contactor's lifespan and switching reliability. Ensure adequate ventilation if operating near the upper limits.

When installing in extreme environments, consider factors like direct sunlight exposure or proximity to heat-generating equipment. These can artificially raise the local ambient temperature and potentially impact the contactor's performance.

10. Can auxiliary contacts be added to the Siemens 3RT2027-1AK60?

Yes, the Siemens 3RT2027-1AK60 is designed to accommodate add-on auxiliary contact blocks. It typically comes with one integrated NO and one integrated NC auxiliary contact, but additional blocks can be mounted on the front.

These add-on blocks expand the contactor's functionality for control and signaling purposes. You can add more NO or NC contacts, or even special function contacts, to meet complex control logic requirements.

The ability to add auxiliary contacts enhances the versatility of the 3RT2027-1AK60, allowing it to be integrated into sophisticated automation systems for status feedback, interlocking, or alarm functions. Always ensure compatibility when selecting add-on modules.