Siemens 3RT5035-1AL20 Industrial Grade AC Contactor 230VAC 40A 3NO

The Siemens 3RT5035-1AL20 is a robust, industrial-grade AC contactor engineered for reliable power switching in demanding applications. This 230VAC, 40A, 3NO (normally open) device offers exceptional durability, compact design, and straightforward integration into various control systems. Its high switching capacity and long electrical lifespan make it a cost-effective and dependable choice for motor control, power distribution, and general switching duties across multiple industrial sectors.

Product Specifications

| Feature             | Specification                               |

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

| Product Type        | Industrial Grade AC Contactor               |

| Manufacturer        | Siemens                                     |

| Model Number        | 3RT5035-1AL20                               |

| Coil Voltage        | 230 VAC                                     |

| Rated Current (AC-3) | 40 A                                        |

| Number of NO Poles  | 3                                           |

| Auxiliary Contacts  | 1 NO + 1 NC (integrated, not on base model) |

| Mounting            | Rail or Screw Mount                         |

| Protection Class    | IP20                                        |

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

Core Features & Market Positioning

The Siemens 3RT5035-1AL20 distinguishes itself through its rugged construction and Siemens' renowned reliability in industrial automation. Designed to meet stringent IEC standards, this contactor offers a significant advantage in applications requiring high operational continuity. Its compact footprint allows for space-saving installations in control cabinets, a critical factor in modern industrial panel design. Compared to other contactors in its class, the 3RT5035-1AL20 provides a superior balance of performance, durability, and cost-effectiveness, positioning it as a preferred component for system integrators and maintenance engineers seeking dependable solutions.

Key Application Scenarios

This Siemens contactor finds extensive use in motor control circuits for starting, stopping, and reversing three-phase motors. Its 40A rating makes it suitable for a wide range of industrial machinery, including pumps, fans, compressors, and conveyors. Beyond motor control, the 3RT5035-1AL20 is utilized in power distribution systems for load switching and in lighting control applications where robust switching capabilities are paramount. Industries such as manufacturing, material handling, water treatment, and building automation frequently specify this model for its versatility and reliable performance under continuous operational loads.

Practical System Integration Guidance

Integrating the Siemens 3RT5035-1AL20 into existing systems is typically straightforward. The unit supports standard DIN rail mounting, simplifying installation within control panels. For screw mounting, appropriate fasteners should be used to ensure a secure connection. Wiring involves connecting the power terminals (L1, L2, L3 and T1, T2, T3) to the load and supply, while the coil terminals (A1, A2) are connected to the 230VAC control circuit. It is crucial to adhere to local electrical codes and ensure proper wire sizing for the 40A rating to prevent overheating and ensure safety. The addition of auxiliary contact blocks, if required, can be easily snapped onto the front of the contactor, enabling feedback to control systems or interlocking functions.

Operation and Risk Mitigation

Proper operation of the Siemens 3RT5035-1AL20 involves ensuring the coil voltage precisely matches the 230VAC supply to prevent premature failure or malfunction. Users should always verify that the load current does not exceed the contactor's AC-3 rating. To mitigate risks, regular inspection for signs of wear, such as pitting on the contacts or damage to the housing, is recommended. Maintenance should be performed only after the power supply has been completely isolated and verified. While specific error codes are not inherent to the contactor itself, system-level diagnostics should monitor for abnormal switching behavior or coil circuit faults, which could indicate a problem with the contactor or its control circuit.

Scalability & Long-Term Value

The Siemens 3RT5035-1AL20 offers significant long-term value due to its compatibility with a broad spectrum of Siemens industrial control components and its adherence to international standards. This ensures that it can be readily integrated into both new and existing automation architectures, including those that may incorporate IIoT capabilities through compatible controllers or gateways. While the 3RT5035-1AL20 is a fixed configuration, Siemens' wider SIRIUS line provides scalable options for higher current ratings or different pole configurations, allowing for seamless upgrades or expansions within a unified system design.

Frequently Asked Questions (FAQs)

What is the primary function of the Siemens 3RT5035-1AL20?

It acts as an electrically operated switch for controlling high-power circuits. It's commonly used to start and stop motors safely.

This contactor allows remote control of electrical loads. It safely handles significant current in industrial settings.

Its main role is to make or break electrical connections under load conditions. This ensures system safety and control.

What are the key technical specifications of the Siemens 3RT5035-1AL20?

The coil voltage is 230 VAC, and it's rated for 40A under AC-3 load conditions. It features three normally open (NO) poles.

This model is designed for industrial use, ensuring robust performance. Its compact design aids in panel space optimization.

It offers reliable switching for demanding applications. It meets stringent IEC standards for industrial components.

Can the Siemens 3RT5035-1AL20 be used for DC applications?

No, this specific model is designed exclusively for AC circuits. Using it with DC loads can cause damage and hazards.

AC contactors like the 3RT5035-1AL20 have different arc suppression. DC circuits require specialized DC contactors.

Always verify the product's intended application and voltage type before installation. Check datasheets for DC-rated alternatives if needed.

How do I wire the Siemens 3RT5035-1AL20?

Connect the main power terminals to the load and supply. Wire the coil terminals (A1/A2) to the 230 VAC control voltage source.

Ensure proper wire gauge for the 40A rating. Follow all local electrical codes during installation.

Auxiliary contacts can be added for control feedback or interlocking functions. Consult the manual for specific wiring diagrams.

What is the significance of "3NO" in the product name?

"3NO" indicates that the contactor has three poles, and each pole is normally open. This means the contacts are closed when the coil is energized.

These three sets of contacts are used to switch three separate conductors simultaneously. This is ideal for three-phase motor control.

When the coil receives 230 VAC, these three NO contacts close, completing the power circuit. Upon de-energization, they revert to their open state.

What is the maximum ambient operating temperature for this contactor?

The Siemens 3RT5035-1AL20 can operate reliably in temperatures ranging from -25°C to +60°C. This wide range ensures functionality in diverse industrial environments.

Ensure adequate ventilation around the contactor within control cabinets. Overheating can reduce its lifespan and performance.

Adhering to the specified temperature limits is crucial for maintaining operational integrity and safety. Check datasheets for specific derating curves if operating near limits.

Does this contactor come with auxiliary contacts?

The base Siemens 3RT5035-1AL20 model does not include auxiliary contacts, but they can be easily added. Many versions are available for snap-on mounting.

Optional auxiliary contact blocks typically offer configurations like 1 NO + 1 NC. These are essential for control system feedback or interlocks.

Verify the specific part number or consult the product documentation to confirm if auxiliary contacts are included or available for your chosen configuration.

What type of mounting is supported by the 3RT5035-1AL20?

This contactor supports both standard 35mm DIN rail mounting and direct screw mounting. This flexibility accommodates various control panel designs.

Ensure secure mounting to prevent vibration-related issues. Use appropriate hardware for screw mounting to the panel.

Proper mounting ensures good thermal dissipation and electrical connection integrity. Consult the installation manual for detailed guidance.

How does this contactor differ from a relay?

Contactors are designed for higher power loads and more frequent switching than relays. They are built with more robust materials for industrial environments.

While both use an electromagnet to operate contacts, contactors typically handle currents from 9A upwards. Relays are generally for lower current control signals.

The 3RT5035-1AL20 is specifically engineered for motor control and power switching, whereas relays are often used for logic and signaling circuits.

What safety precautions should be taken when installing or servicing this contactor?

Always de-energize the entire circuit before performing any installation or maintenance work. Lockout/tagout procedures must be followed.

Verify that the correct coil voltage (230 VAC) is applied. Ensure proper grounding of the control panel and equipment.

Wear appropriate personal protective equipment (PPE), including safety glasses and insulated gloves. Double-check all connections before re-energizing the system.