Siemens 3RT2028-1AP00 High Power AC Contactor for Heavy Duty 230VAC 38A 3NO

The Siemens 3RT2028-1AP00 is a robust, high-power AC contactor engineered for demanding industrial applications. This 3-pole, normally open (3NO) device boasts a significant 38A rating and operates on a 230VAC coil voltage, making it a cornerstone for heavy-duty load switching. Its inherent reliability and Siemens' renowned build quality position it as a preferred choice for professionals seeking dependable power control solutions. Key advantages include its high switching capacity, compact design for space-constrained enclosures, and straightforward integration into existing control systems.

Product Specifications

| Feature              | Specification                    |

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

| Product Type         | Power Contactor                  |

| Manufacturer         | Siemens                            |

| Series               | 3RT2 SIRIUS                      |

| Model Number         | 3RT2028-1AP00                    |

| Number of Poles      | 3                                |

| Number of NO Contacts | 3                                |

| Rated operational current (AC-1, 400V) | 38 A                             |

| Coil Voltage         | 230 VAC                          |

| Auxiliary Contacts   | Not Integrated (Optional)        |

| Mounting Type        | Rail Mount                       |

| Protection Rating    | IP20                             |

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

| Dimensions (H x W x D) | 84 mm x 55 mm x 98 mm              |

| Weight               | 0.36 kg                          |

Core Features & Market Positioning

The Siemens 3RT2028-1AP00 distinguishes itself through its adherence to stringent international standards, ensuring safety and operational integrity in diverse environments. Its SIRIUS innovation platform means it offers superior reliability and extended service life compared to many competitors, a critical factor in reducing downtime and maintenance costs for industrial operations. This contactor is designed for high switching frequencies, making it suitable for applications requiring frequent on/off cycles without premature wear. Its market positioning is firmly within the heavy-duty industrial control sector, catering to applications where performance under load and long-term dependability are paramount. The Siemens brand itself carries significant weight, assuring users of quality and advanced engineering.

Key Application Scenarios

This high-power contactor is ideally suited for direct on-line (DOL) starting of medium-sized three-phase motors, a fundamental requirement in manufacturing plants, material handling systems, and pump control applications. It excels in controlling heating circuits, capacitor banks, and general inductive loads where significant current is involved. Industries such as food and beverage processing, water treatment, and HVAC systems frequently rely on contactors like the 3RT2028-1AP00 for robust motor control and power switching. Its 230VAC coil voltage makes it compatible with standard control power supplies found in many industrial settings.

Practical System Integration Guidance

Integrating the Siemens 3RT2028-1AP00 into an electrical control panel is a streamlined process. It mounts directly onto a standard 35mm DIN rail, facilitating quick installation and secure positioning. For wiring, the main power terminals are clearly marked for incoming and outgoing power to the load, typically a motor. The 230VAC coil can be wired to a suitable control circuit, often through a PLC output or a manual control switch, ensuring the contactor energizes and de-energizes the load as required. It's crucial to adhere to local electrical codes and ensure proper circuit protection, such as appropriately sized fuses or circuit breakers, upstream of the contactor.

Operation and Risk Mitigation

Proper operation of the Siemens 3RT2028-1AP00 relies on ensuring the coil voltage precisely matches the 230VAC supply and that the load current does not exceed the contactor's rated 38A capacity. Overloading is a primary risk that can lead to premature contact welding or coil failure. Regular inspection of the electrical connections for tightness and signs of overheating is recommended. In case of malfunction, such as a failure to energize or de-energize, the first steps should involve verifying the control voltage and checking for obstructions. Always ensure power is de-energized before performing any maintenance or inspection to mitigate electrical shock hazards.

Scalability & Long-Term Value

The SIRIUS 3RT2 series, to which the 3RT2028-1AP00 belongs, offers excellent scalability through its modular design. Additional auxiliary contact blocks (normally open or normally closed) can be easily snapped onto the front or side of the contactor to expand its control and signaling capabilities. This allows for future integration of more complex control logic or monitoring functions without replacing the main contactor. Furthermore, these contactors are designed for compatibility within the broader Siemens industrial automation ecosystem, including PLCs and motor starters, enabling seamless integration into more advanced digital manufacturing or IIoT platforms as operational needs evolve.

Frequently Asked Questions (FAQs)

Q1: What is the maximum motor horsepower this contactor can handle?

The Siemens 3RT2028-1AP00 is rated for 38A at AC-1 loads. For motor applications, the horsepower rating depends on the motor's specific characteristics and starting current. Typically, it can handle motors up to 15-20 HP at 400V for direct-on-line starting, but consulting specific motor data sheets is essential.

This contactor is designed for heavy-duty switching of significant electrical loads. Its robust construction ensures reliable operation in demanding industrial environments. Professionals should always verify the motor's nameplate data against the contactor's specifications for safe and efficient operation.

Consider the duty cycle and specific application requirements when determining the optimal horsepower for motor control. Always refer to the Siemens technical documentation for precise application guidelines and motor ratings.

Q2: Can I use this contactor for DC loads?

No, the Siemens 3RT2028-1AP00 is specifically designed and rated for AC (Alternating Current) loads. Using it for DC (Direct Current) applications is not recommended and can lead to improper operation, contact damage, or failure due to the arc characteristics of DC switching.

AC contactors have specific contact designs and arc suppression mechanisms optimized for AC. DC loads require contactors with different specifications, often including series resistors or different contact materials to manage the sustained arc.

Always select a contactor explicitly rated for the type of current (AC or DC) and voltage you intend to control. Siemens offers specific DC contactor series if your application requires it.

Q3: What type of auxiliary contacts are compatible with the 3RT2028-1AP00?

This contactor is designed to accept snap-on auxiliary contact blocks. You can add combinations of normally open (NO) and normally closed (NC) contacts to expand its control and signaling functions. These blocks attach easily to the front or side of the main power module.

The SIRIUS 3RT2 series supports modular auxiliary contacts that are easily installed without special tools. This allows for customization to meet specific control circuit requirements, such as feedback signals or interlocks.

Ensure you select auxiliary contact blocks designed for the 3RT2 series to guarantee proper fit and electrical performance. Check the product's datasheet for compatible accessory part numbers.

Q4: What is the expected lifespan of this Siemens contactor?

The lifespan of the Siemens 3RT2028-1AP00 is measured in electrical switching cycles and depends heavily on the application's load conditions and switching frequency. Under typical industrial conditions, it offers a high number of switching operations, often in the millions for lighter loads.

Siemens SIRIUS components are known for their durability and long service life, thanks to high-quality materials and robust design. Factors like frequent high inrush currents or switching inductive loads can reduce the total number of cycles achievable.

For applications with very high switching frequencies or demanding loads, consulting the detailed technical specifications or Siemens support can provide more precise endurance data and recommendations.

Q5: How do I wire the 230VAC coil of the 3RT2028-1AP00?

The coil is typically energized by applying 230VAC to terminals A1 and A2, which are clearly marked on the contactor. Ensure the control circuit voltage is stable and matches the specified 230VAC rating to prevent coil damage.

Connect the live 230VAC supply to one terminal (e.g., A1) and the neutral or switched control signal to the other terminal (e.g., A2) through your control system (PLC, switch, etc.). Always follow proper wiring practices and local electrical codes.

Before making connections, verify the power to the control circuit is off. Proper wiring ensures the contactor will reliably switch on and off according to your control signals.

Q6: What ambient temperature range is suitable for operating this contactor?

The Siemens 3RT2028-1AP00 is designed to operate reliably within an ambient temperature range of -25°C to +60°C (-13°F to +140°F). This wide range makes it suitable for a variety of industrial environments, from cold storage to moderately heated areas.

Exceeding these temperature limits can affect the contactor's performance, potentially leading to reduced lifespan or premature failure. Ensure adequate ventilation within enclosures where the contactor is installed, especially in warmer environments.

Consider derating the contactor's current carrying capacity if operating consistently at the upper limits of this temperature range, particularly if enclosed. Always consult the manufacturer's datasheet for detailed environmental performance.

Q7: Does this contactor come with overload protection?

No, the Siemens 3RT2028-1AP00 is a power contactor and does not include integrated overload protection. Overload relays or electronic overload monitors are separate devices that must be selected and wired into the control circuit upstream or in conjunction with the contactor.

Overload protection is crucial for preventing motor damage from sustained overcurrent conditions, such as those caused by mechanical overload or phase loss. This protection is typically achieved using devices like the Siemens 3RU or 3RB series.

You must specify and install an appropriate overload protection device tailored to the motor's full load current and characteristics to ensure safety and prevent equipment damage.

Q8: What is the IP rating of the Siemens 3RT2028-1AP00?

The Siemens 3RT2028-1AP00 has an IP20 rating. This means it is protected against solid objects greater than 12.5mm in diameter (like a finger) but offers no protection against water ingress.

This rating indicates it is suitable for installation within control cabinets or enclosures where it is protected from direct contact and environmental elements like dust and moisture. It is not intended for direct exposure to outdoor or wet conditions.

For applications requiring higher environmental protection, consider installing the contactor within a suitable enclosure that meets the required IP rating for the specific environment.

Q9: Can I use this contactor for frequent switching applications?

Yes, the Siemens 3RT2028-1AP00 is built for demanding industrial use and supports a high electrical endurance, making it suitable for frequent switching. However, the exact number of switching cycles achievable is load-dependent.

For applications involving very high switching frequencies (e.g., multiple times per minute), it's advisable to consult the detailed technical documentation for specific electrical endurance ratings under those conditions. Proper selection of auxiliary contacts also plays a role.

Consider factors like inrush current and power factor of the load. If the switching frequency is extremely high, evaluating alternative solutions or ensuring adequate cooling might be necessary.

Q10: What is the difference between a contactor and a relay?

Contactors and relays are both electromechanical switches, but contactors are generally designed for higher power loads. Contactors typically have higher current ratings, more robust construction, and are specifically intended for switching motors and heavy industrial equipment.

Relays are typically used for lower power applications, such as switching control signals, lighting, or small electronic loads. They often have more poles and smaller contact arrangements compared to contactors.

While both operate on a coil to open or close contacts, the primary distinction lies in their intended application and capacity for handling power. A contactor is essentially a heavy-duty relay.