Siemens 3RT2027-1AL20 SIRIUS High Power Motor Control Contactor 230VAC 32A 3NO

Siemens 3RT2027-1AL20 SIRIUS High Power Motor Control Contactor: Robust Power Switching for Industrial Applications

The Siemens 3RT2027-1AL20 SIRIUS Power Contactor is engineered for reliable and efficient motor control in demanding industrial environments. This 3-pole contactor, suitable for AC-3e/AC-3 applications, boasts a significant 32A rating and a 15 kW power capacity at 400V. Operating on a 230V AC coil voltage, it offers robust switching capabilities with integrated 1 Normally Open (NO) and 1 Normally Closed (NC) auxiliary contacts, facilitating sophisticated control and signaling circuits. Its compact Size S0 design and screw-clamp terminal connections ensure straightforward integration into control panels. With a mechanical service life of up to 10 million operations, the 3RT2027-1AL20 represents a durable and cost-effective solution for a wide array of motor control needs.

Product Specifications

| Feature                     | Specification                                          |

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

| Product Brand Name          | SIRIUS                                                 |

| Product Designation         | Power Contactor                                        |

| Product Type Designation    | 3RT2                                                   |

| Size of Contactor           | S0                                                     |

| Number of Poles             | 3                                                      |

| Rated Operational Current (AC-3e/AC-3) | 32 A                                                   |

| Rated Active Power (400V)   | 15 kW                                                  |

| Control Coil Voltage        | 230 V AC (50/60 Hz)                                    |

| Auxiliary Contacts          | 1 NO + 1 NC                                            |

| Connection Type             | Screw-clamp terminals                                  |

| Rated Insulation Voltage    | 690 V                                                  |

| Rated Impulse Voltage       | 6 kV                                                   |

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

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

| Degree of Protection        | IP20                                                   |

| Dimensions (L x W x H)      | 92.00 x 54.00 x 105.50 mm                              |

| Net Weight                  | 0.423 kg                                               |

| Country of Origin           | Germany                                                |

Core Features & Market Positioning

The Siemens 3RT2027-1AL20 SIRIUS Power Contactor distinguishes itself through its robust construction and adherence to stringent IEC standards (IEC 60947-1, IEC 60947-4-1). This commitment to quality engineering ensures reliable operation and a long operational lifespan, even under demanding industrial conditions. Its S0 size offers a compact footprint, making it suitable for space-constrained control cabinets, a significant advantage in modern automation systems where panel real estate is at a premium. The integrated auxiliary contacts (1 NO + 1 NC) simplify wiring and reduce the need for external components, streamlining control circuit design. Compared to its predecessor, the 3RT1034-1AL20, the 3RT2027-1AL20 offers advancements in performance and reliability, positioning it as a current-generation solution for motor control applications. Its IE3/IE4-ready status also aligns with energy efficiency mandates, further enhancing its market appeal.

Key Application Scenarios

This Siemens contactor is ideally suited for direct-on-line (DOL) motor starting applications across various industrial sectors. Its 32A rating and 15kW power capacity at 400V make it a versatile choice for controlling medium-sized three-phase motors used in manufacturing, material handling, pumps, fans, and HVAC systems. The 230V AC coil voltage ensures compatibility with standard control power supplies commonly found in industrial facilities. The inclusion of both NO and NC auxiliary contacts allows for interlocking, signaling, and integration into more complex control logic, such as in reversing contactor assemblies or star-delta starter configurations when used with appropriate accessories.

Practical System Integration Guidance

Integrating the Siemens 3RT2027-1AL20 into existing or new control systems is facilitated by its user-friendly screw-clamp terminals, which offer a secure and reliable connection. For installations requiring vibration resistance or faster assembly, Siemens also offers variants with spring-type terminals, ensuring flexibility in application. When wiring, it is crucial to adhere to local electrical codes and safety regulations. The contactor can be mounted directly onto a standard DIN rail or via surface mounting, providing installation flexibility. For optimal performance and longevity, ensure the ambient temperature remains within the specified operating range of -25°C to +60°C. While detailed wiring diagrams are best sourced from the official Siemens documentation, common practice involves connecting the main power terminals (L1, L2, L3) to the motor supply and the output terminals to the motor itself. The control coil is energized by the 230V AC supply, typically via a control circuit that includes protection devices like fuses or circuit breakers. The integrated auxiliary contacts can be wired into control logic for status feedback or interlocks.

Operation and Risk Mitigation

Safe operation of the Siemens 3RT2027-1AL20 hinges on proper installation, adherence to electrical codes, and appropriate system protection. The contactor is designed with a degree of protection IP20, meaning it protects against solid objects greater than 12.5 mm but offers no protection against water ingress. Therefore, it must be installed in an enclosure or environment that provides adequate protection against dust, moisture, and physical damage. Overload protection for the motor being controlled should be provided by a separate device, such as a Siemens 3RU overload relay, to prevent motor damage due to sustained overcurrent conditions. Electrical hazards associated with contactors include arc flash and electrical shock. To mitigate these risks, always de-energize the circuit before performing any maintenance or wiring. Use appropriate personal protective equipment (PPE), including insulated gloves and safety glasses. The mechanical durability of 10 million cycles is a testament to its robust design, but like any electromechanical device, failure is possible. Siemens provides B10 values/failure rates for its SIRIUS products, which can be referenced for risk assessments.

Scalability & Long-Term Value

The SIRIUS modular system, to which the 3RT2027-1AL20 belongs, is designed for scalability and integration with modern industrial automation platforms. This contactor can be easily incorporated into larger motor control centers (MCCs) or integrated with programmable logic controllers (PLCs) for advanced control and monitoring. Its compatibility with various SIRIUS accessories, such as auxiliary switch blocks and communication modules, allows for future system expansion and functional upgrades. For applications requiring enhanced diagnostics or remote control, integration with industrial communication protocols like IO-Link is possible, aligning with the principles of Industry 4.0 and the Industrial Internet of Things (IIoT). This forward-looking design ensures that the 3RT2027-1AL20 remains a valuable component throughout the lifecycle of an automated system.

Frequently Asked Questions (FAQs)

Q1: What is the primary application for the Siemens 3RT2027-1AL20?

The Siemens 3RT2027-1AL20 is primarily used as a power contactor for switching electric motors in industrial applications. It is particularly suited for direct-on-line (DOL) starting of three-phase motors. Its robust design and 32A rating make it suitable for controlling motors up to 15 kW at 400V.

This contactor is a key component in motor control centers, pump stations, fan systems, and various manufacturing machinery where reliable on/off switching of motor loads is essential. The integrated auxiliary contacts also enable basic interlocking and signaling functions.

Its compatibility with standard 230V AC control circuits and its robust construction ensure it can handle the rigors of continuous industrial operation.

Q2: What type of auxiliary contacts does the Siemens 3RT2027-1AL20 have?

The Siemens 3RT2027-1AL20 comes equipped with integrated auxiliary contacts. Specifically, it features one Normally Open (NO) contact and one Normally Closed (NC) contact.

These auxiliary contacts are vital for building control circuits, enabling functions such as interlocking between contactors, providing status feedback to control systems, or activating alarm signals. They simplify wiring by reducing the need for external auxiliary contact blocks.

The presence of both NO and NC contacts offers flexibility in designing control logic, accommodating various interlocking schemes and signaling requirements.

Q3: What is the coil voltage for the Siemens 3RT2027-1AL20?

The Siemens 3RT2027-1AL20 features a coil voltage of 230V AC. This voltage is standard for control circuits in many industrial settings worldwide.

This specific coil voltage allows the contactor to be easily integrated into existing control panels that operate with a 230V AC supply for their control logic. It simplifies power distribution within the control cabinet.

Users should ensure their control power supply matches the 230V AC requirement to properly energize the coil and ensure the contactor operates as intended.

Q4: Can the Siemens 3RT2027-1AL20 be used for DC motor control?

No, the Siemens 3RT2027-1AL20 is specifically designed for AC motor control. Its coil and main contacts are rated for alternating current (AC) operation.

Using this contactor for DC motor control would lead to improper operation and potential damage to the device, as DC circuits have different switching characteristics and arc suppression requirements.

For DC motor control, Siemens offers specialized contactors designed for direct current applications, which should be selected instead.

Q5: What is the IP rating of the Siemens 3RT2027-1AL20?

The Siemens 3RT2027-1AL20 has an IP20 degree of protection. This rating indicates that the contactor is protected against solid objects larger than 12.5 mm, such as fingers.

However, the IP20 rating means it offers no protection against water or moisture. Therefore, it must be installed within an enclosure or a control panel that provides adequate protection against environmental factors.

Proper enclosure is crucial to prevent ingress of dust, moisture, or other contaminants that could lead to malfunction or failure of the contactor.

Q6: What is the rated power of the Siemens 3RT2027-1AL20?

The Siemens 3RT2027-1AL20 has a rated power of 15 kW at 400V AC, specifically for AC-3e/AC-3 duty applications. This rating signifies its capability to handle motor loads under typical starting and running conditions.

This power rating makes it suitable for controlling a wide range of medium-sized industrial motors, ensuring reliable operation without exceeding the contactor's capacity. It is a key parameter for selecting the correct contactor for a specific motor.

When selecting a contactor, always consider the motor's nameplate power rating and its operating duty cycle to ensure proper application.

Q7: How is the Siemens 3RT2027-1AL20 mounted?

The Siemens 3RT2027-1AL20 offers versatile mounting options. It can be easily installed on a standard 35 mm DIN rail, which is a common method in industrial control panels.

Additionally, it supports surface mounting, allowing for flexible installation directly onto a panel or backplate using appropriate mounting hardware. This adaptability ensures it can fit into various cabinet designs and configurations.

These mounting choices provide integrators with the flexibility needed to optimize panel layout and accessibility.

Q8: What is the mechanical service life of this contactor?

The Siemens 3RT2027-1AL20 boasts a significant mechanical service life of up to 10 million operating cycles. This figure represents the number of times the contactor can operate (open and close) without mechanical failure.

This extended mechanical durability ensures a long operational lifespan for the contactor, reducing the frequency of replacements and associated maintenance costs. It is a testament to the robust engineering of the SIRIUS line.

While mechanical life is high, electrical life can be shorter depending on the load and switching frequency; however, this contactor is designed for robust electrical performance.

Q9: Does the 3RT2027-1AL20 support communication protocols like IO-Link?

The standard 3RT2027-1AL20 itself does not directly integrate IO-Link communication. However, it is part of the broader SIRIUS modular system, which allows for connectivity via communication modules.

Siemens offers accessories and interface modules that can be added to contactors like the 3RT2027-1AL20 to enable communication over industrial networks, including IO-Link. This allows for advanced diagnostics and integration into IIoT systems.

By leveraging these accessories, the contactor can be made "smart," providing valuable data for predictive maintenance and process optimization in Industry 4.0 environments.

Q10: Can this contactor replace older Siemens contactors?

Yes, the Siemens 3RT2027-1AL20 is designed as a successor to older models. It replaces the well-proven 3RT1 series, offering enhanced performance and modern features.

Specifically, it is noted to replace older parts like the 3RT1034-1AL20, indicating a direct upgrade path for existing installations. This allows for modernization of control systems with improved reliability and efficiency.

When replacing older contactors, always verify that the electrical ratings, coil voltage, and physical dimensions are compatible or that necessary modifications to the control system are made.