Siemens 3RT2628-1AP05 Standard Industrial Motor Control Contactor

The Siemens 3RT2628-1AP05 is a high-performance industrial motor control contactor designed for the demanding task of switching capacitive loads. This 3-pole contactor, specifically part of the SIRIUS 3RT26 series, excels in applications such as capacitor banks and converters, offering a rated blind power of 33 kVAR at 400V. Its compact S0 size and screw terminal connections facilitate straightforward integration into control panels, while the integrated 1 NO + 2 NC auxiliary contacts provide essential control and monitoring capabilities. Operating with a 230V AC, 50Hz coil voltage, this contactor ensures compatibility with standard industrial power supplies, delivering reliability and efficiency for power factor correction systems.

Product Specifications

| Feature                      | Specification                                     |

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

| Product Type                 | Capacitor Contactor                               |

| Series                       | SIRIUS 3RT26                                      |

| Poles                        | 3-pole                                            |

| Rated Blind Power (400V, 50Hz) | 33 kVAR                                           |

| Coil Voltage                 | 230V AC, 50Hz                                     |

| Auxiliary Contacts           | 1 Normally Open (NO) + 2 Normally Closed (NC)     |

| Terminal Type                | Screw Terminal                                    |

| Contactor Size               | S0                                                |

| AC-6b Rating                 | Yes                                               |

| Dimensions (L x W x H)       | 160.00 x 160.00 x 60.00 mm (approximate)          |

| Net Weight                   | 0.661 Kg                                          |

| Insulation Voltage (Main)    | 690 V                                             |

| Insulation Voltage (Auxiliary)| 690 V                                             |

| Surge Voltage Resistance     | 6 kV                                              |

| Mechanical Service Life      | 3,000,000 cycles (typical with auxiliary switch)  |

| Electrical Endurance         | 150,000 cycles                                    |

| Ambient Temperature (Operation)| -25°C to +60°C                                    |

| Ambient Temperature (Storage) | -55°C to +80°C                                    |

| Protection Directives        | RoHS compliant (since 01.05.2014)                 |

| Country of Origin            | Germany                                           |

Core Features & Market Positioning

The Siemens 3RT2628-1AP05 stands out in the industrial control market due to its specialized design for capacitive loads, operating under the AC-6b category. This rating signifies enhanced capability for switching the high inrush currents typical of capacitor banks and converters, ensuring greater reliability and a longer operational lifespan compared to general-purpose contactors. Siemens' SIRIUS modular system provides a robust platform, allowing for seamless integration with other SIRIUS components. This product embodies Siemens' commitment to providing high-performance, reliable, and user-friendly solutions for critical industrial power management tasks, positioning it as a premium choice for applications demanding precision and durability. Its climate-resistant construction and global approvals (IEC, UL/CSA) further solidify its market position for diverse international deployments.

Key Application Scenarios

The primary application for the Siemens 3RT2628-1AP05 is in power factor correction systems where automatic capacitor banks are utilized to maintain optimal voltage levels and reduce energy costs by compensating for reactive power. It is crucial for switching individual capacitor stages within these banks, ensuring that the correct amount of capacitance is brought online or taken offline as load conditions vary. Beyond static capacitor banks, this contactor is also ideal for controlling converters and other capacitive loads in industrial settings, including manufacturing plants, data centers, and any facility with significant inductive loads requiring reactive power compensation. Its AC-6b rating is particularly beneficial in these scenarios due to the repetitive switching demands and potential for high inrush currents.

Practical System Integration Guidance

Integrating the Siemens 3RT2628-1AP05 into an existing or new control system is streamlined due to its S0 size and standard 230V AC coil voltage, ensuring broad compatibility. The screw terminals offer a secure and efficient method for wiring, simplifying installation and maintenance procedures. When implementing capacitor switching, it is vital to ensure that the contactor's rating (AC-6b) is appropriately matched to the capacitor's reactive power and the system voltage. For systems with frequent switching or high transient currents, consider using auxiliary contactors or specialized capacitor switching modules designed to pre-charge capacitors and suppress inrush currents, thereby protecting the main contactor. Always adhere to local electrical codes and safety standards during installation.

Operation and Risk Mitigation

The Siemens 3RT2628-1AP05 operates by electromagnetically switching main power contacts to connect or disconnect capacitive loads. Proper operation relies on supplying the correct control voltage to the coil. Risk mitigation in its operation primarily involves ensuring correct application sizing, preventing overload conditions, and performing regular maintenance. Overheating, excessive switching frequency beyond its electrical endurance, or using the contactor for applications outside its AC-6b rating can lead to premature failure. Troubleshooting typically involves checking coil voltage, verifying contact continuity, and inspecting for mechanical wear or damage. While specific fault codes are not inherent to the contactor itself, system diagnostics should monitor for anomalies in power factor, voltage fluctuations, or tripping of upstream protection devices, which could indicate issues with the contactor or the capacitor bank it controls.

Scalability & Long-Term Value

The Siemens 3RT2628-1AP05 benefits from the expansive SIRIUS modular system, offering significant scalability and long-term value. Its compatibility with a wide range of SIRIUS accessories, such as auxiliary contact blocks, surge suppressors, and communication modules (though this specific model may not have direct IIoT communication), allows for system expansion and adaptation to evolving industrial needs. The standardized design ensures that it can be easily replaced or supplemented within existing SIRIUS-based control panels. For facilities moving towards Industry 4.0, integrating this contactor as part of a larger system managed by programmable logic controllers (PLCs) and supervisory control and data acquisition (SCADA) systems provides a foundation for data collection and remote monitoring, contributing to the overall digitalization of operations.

Frequently Asked Questions (FAQs)

What is the primary application for the Siemens 3RT2628-1AP05?

The Siemens 3RT2628-1AP05 is primarily designed for switching capacitive loads, such as capacitor banks in power factor correction systems. Its AC-6b rating is specifically optimized for handling the high inrush currents associated with connecting and disconnecting capacitors. This makes it ideal for maintaining stable voltage and improving energy efficiency in industrial facilities.

This contactor ensures reliable operation in demanding switching scenarios. It is crucial for applications where precise reactive power compensation is required to meet energy standards and reduce electrical costs. The specialized AC-6b classification highlights its ability to withstand the unique electrical stresses of capacitive loads.

Its use extends to controlling converters and other reactive loads that benefit from specialized switching capabilities. The robust design ensures longevity even with frequent switching cycles.

What are the key technical specifications of the Siemens 3RT2628-1AP05?

This 3-pole capacitor contactor is rated for 33 kVAR at 400V AC and features a 230V AC, 50Hz coil voltage. It includes 1 normally open (NO) and 2 normally closed (NC) auxiliary contacts for control and monitoring. The contactor is size S0, equipped with screw terminals for easy installation. It also boasts an insulation voltage of 690V for both main and auxiliary circuits and a 6kV surge voltage resistance.

The device is built for durability, offering a mechanical service life of up to 3 million cycles and an electrical endurance of 150,000 cycles. Its operational ambient temperature range is -25°C to +60°C. Compliance with RoHS directives is ensured since May 1, 2014.

The compact dimensions (approx. 160x160x60mm) and a net weight of about 0.661kg facilitate its integration into standard control cabinets. Its German origin underscores Siemens' commitment to quality manufacturing.

How does the AC-6b rating benefit this contactor in applications?

The AC-6b rating signifies that the Siemens 3RT2628-1AP05 is specifically designed and tested for switching capacitive loads, offering superior performance and longevity compared to general-purpose contactors. This rating ensures it can effectively manage the very high inrush currents that occur when connecting capacitor banks to the power supply. These transient currents can be many times the rated current, posing a significant risk to standard contactors.

By employing specialized contact materials and designs, AC-6b contactors like the 3RT2628-1AP05 can withstand these high-frequency, high-magnitude current surges without significant wear or damage to the contacts. This protection is vital for the reliable and extended operation of capacitor banks used in power factor correction.

Consequently, choosing a contactor with an AC-6b rating for capacitive loads dramatically reduces the risk of premature failure, costly downtime, and potential damage to other components within the power system. It represents a critical factor in ensuring the stability and efficiency of power quality systems.

What are the main advantages of using the Siemens 3RT2628-1AP05?

A key advantage is its specialized AC-6b rating, making it ideal for switching capacitive loads like capacitor banks, offering enhanced durability and reliability. The integration into the SIRIUS modular system allows for easy combination with other Siemens components, simplifying system design and expansion. Its compact S0 size and screw terminals facilitate straightforward installation and space-saving in control panels.

Furthermore, the contactor is climate-resistant and approved for worldwide use, including IEC and UL/CSA standards, ensuring broad applicability and compliance. The inclusion of 1 NO and 2 NC auxiliary contacts provides immediate control and monitoring capabilities without requiring additional accessories for basic functions.

This combination of specialized design, system integration, and robust construction provides a cost-effective and dependable solution for power factor correction and similar industrial applications.

Can the Siemens 3RT2628-1AP05 be used for motor control applications?

While the Siemens 3RT2628-1AP05 is an industrial contactor, its specific design and AC-6b rating are optimized for switching capacitive loads, not primarily for starting or controlling standard industrial motors. General-purpose power contactors, such as those in the Siemens 3RT20 or 3RT22 series, are designed for motor control applications, offering different AC-3 or AC-1 ratings suited for motor starting or load switching. Using the 3RT2628-1AP05 for direct motor control could lead to premature wear or failure due to its specialized AC-6b characteristics not being appropriate for motor winding currents.

It is crucial to select the correct contactor for the specific application to ensure safety, reliability, and performance. The 3RT26 series is purpose-built for capacitor switching, providing the necessary resilience against high inrush currents typical of these loads.

For motor control, it is recommended to consult the product datasheets for Siemens' power contactors designed for AC-3 utilization categories. These are engineered to handle the mechanical and electrical stresses associated with motor starting and running loads.

What is the control voltage for the Siemens 3RT2628-1AP05?

The Siemens 3RT2628-1AP05 operates with a standard control voltage of 230V AC at a frequency of 50Hz. This specification ensures compatibility with common industrial control power supplies and automation systems found in many facilities. The coil voltage is designed to be robust yet responsive for reliable switching operations.

This choice of control voltage simplifies integration into existing electrical infrastructure. It aligns with typical power distribution found in control cabinets and panels, reducing the need for complex voltage transformation circuits for the coil supply.

Always verify the control voltage requirements before installation to ensure correct operation and prevent damage to the coil. This standard 230V AC coil voltage makes the 3RT2628-1AP05 a practical and widely applicable choice for many power factor correction applications.

How do I install the Siemens 3RT2628-1AP05 contactor?

Installation of the Siemens 3RT2628-1AP05 is facilitated by its S0 size and screw terminals, designed for secure and straightforward connections. The contactor mounts onto a standard DIN rail within a control panel or enclosure. Ensure the power supply to the contactor is de-energized and properly locked out before commencing any wiring.

Connect the main power conductors to the power terminals and the control circuit conductors to the coil terminals (typically marked A1 and A2 for the 230V AC coil). Wire the auxiliary contacts (1 NO, 2 NC) to your control or monitoring system as required. Always follow wiring diagrams provided in the product documentation and adhere to all applicable electrical codes and safety regulations.

For capacitor switching applications, it is critical to ensure proper sizing and integration with protection devices like fuses or circuit breakers. Using pre-charge resistors or limiting inductors may be necessary to manage inrush currents and protect the contactor and capacitors, depending on the specific system design and switching frequency.

What is the rated power handling capacity of the Siemens 3RT2628-1AP05?

The Siemens 3RT2628-1AP05 is rated for a reactive power handling capacity of 33 kVAR at 400V AC and 50Hz. This figure specifically relates to its AC-6b classification, which is tailored for switching capacitor banks. The contactor is designed to effectively switch these capacitive loads and manage the associated inrush currents.

The contactor can also handle operational reactive power ranges from 11 to 33 kvar at 400V, and up to 19 to 57 kvar at 690V, depending on the operating voltage and ambient temperature. This indicates its versatility within different voltage systems, though its primary application remains at or near the 400V level for typical capacitor banks.

It's important to note that this rating is for reactive power compensation. For switching motor loads, a different contactor with an AC-3 rating would be required, as motor starting currents and operational characteristics differ significantly from those of capacitors.

Are there any accessories compatible with the Siemens 3RT2628-1AP05?

Yes, the Siemens 3RT2628-1AP05 is part of the SIRIUS modular system, which offers a wide range of compatible accessories. These can include auxiliary contact blocks (though this model already has integrated ones), surge suppression modules to protect the coil from voltage spikes, and possibly coupling relays or communication modules for integration into advanced control systems. While direct IIoT communication might not be a standard feature of this specific contactor, it can be integrated into a digitally monitored system via other components.

Accessories are designed to enhance functionality, improve reliability, and simplify integration. For instance, surge suppression units can protect the coil from transient overvoltages, extending the contactor's lifespan. Auxiliary contacts can be added to expand control and signaling capabilities beyond the integrated ones.

Always refer to the official Siemens SIRIUS system documentation or consult with a Siemens representative to confirm the exact compatibility and part numbers for desired accessories to ensure optimal system performance and safety.

What is the difference between the 3RT2628-1AP05 and other Siemens contactors?

The primary difference lies in the Siemens 3RT2628-1AP05's specialized AC-6b rating, making it exclusively designed for switching capacitive loads like capacitor banks. Other Siemens contactors, such as those in the 3RT20 or 3RT22 series, are typically rated for AC-1 (general loads) or AC-3 (motor control), which have different electrical characteristics and are unsuitable for the high inrush currents of capacitor switching. For instance, an AC-3 rated contactor is designed to handle motor starting currents, which have different peak values and durations than capacitor inrush currents.

The 3RT26 series, including the 3RT2628-1AP05, incorporates specific design features to mitigate the stress of capacitive switching, such as enhanced contact materials and damping mechanisms to suppress arcing and contact bounce during switching. This ensures longevity and reliability when frequently connecting and disconnecting capacitor stages.

Therefore, while functionally a contactor, the 3RT2628-1AP05 is purpose-built for a niche application and should not be substituted for general-purpose or motor control contactors, nor should other contactors be used for capacitor switching if they lack the appropriate AC-6b rating.