Study on Assembling of Vertical Axis / Horizontal Axis Small Wind Turbine to Produce Electric Power

Wind turbines are devices that convert kinetic energy from the wind into electrical energy, using the principle of electromagnetic induction. There are two main types of wind turbines based on the axis of rotation: Vertical Axis Wind Turbines (VAWTs) and Horizontal Axis Wind Turbines (HAWTs). Both types are used in small-scale systems for generating electricity, particularly for residential, rural, or off-grid applications.

In this study, we will explore the assembly of both vertical axis and horizontal axis small wind turbines, outlining the components, assembly steps, and key considerations in the process.

Objective:

To understand the process of assembling Vertical Axis Wind Turbines (VAWTs) and Horizontal Axis Wind Turbines (HAWTs), specifically designed for small-scale power generation, including the key components and assembly steps involved.

Overview of Vertical Axis and Horizontal Axis Wind Turbines

1. Vertical Axis Wind Turbine (VAWT)

A vertical axis wind turbine has its axis of rotation perpendicular to the ground. The blades are mounted vertically, allowing the turbine to capture wind from any direction without the need for a yaw mechanism. VAWTs are often used in residential applications, urban environments, or areas with turbulent winds.

Key Components of a VAWT:
  • Blades: The blades are the primary components that convert the wind’s kinetic energy into rotational energy. They are often shaped like a helical or curved structure to optimize the wind capture.
  • Shaft: The shaft connects the blades to the generator and transmits the rotational energy.
  • Generator: Converts the mechanical energy from the rotating shaft into electrical energy.
  • Yaw Mechanism: Some VAWTs have passive yaw mechanisms that adjust the turbine orientation automatically, while others do not require yaw systems as they can capture wind from all directions.
  • Support Structure (Tower): Supports the entire turbine assembly, elevating it to an optimal height to capture wind energy.

2. Horizontal Axis Wind Turbine (HAWT)

A horizontal axis wind turbine has its axis of rotation parallel to the ground. It is the most commonly used type of wind turbine and is used for both large-scale and small-scale applications. The blades of a HAWT are designed to rotate on a horizontal axis, and they require a yaw mechanism to adjust the direction of the rotor as the wind changes.

Key Components of a HAWT:
  • Blades: Blades are aerodynamic and designed to capture wind energy, typically made of fiberglass or composite materials.
  • Rotor Hub: The rotor hub holds the blades and connects them to the main shaft.
  • Main Shaft: The main shaft transmits the rotational energy from the rotor hub to the generator.
  • Generator: Converts the mechanical energy from the rotating blades into electrical energy.
  • Yaw Mechanism: The yaw mechanism ensures that the turbine is always facing the direction of the wind. It involves a tail or vane to orient the rotor.
  • Tower: The tower elevates the turbine to ensure optimal wind speed and reduces turbulence near the ground.

Assembly of Vertical Axis Wind Turbine (VAWT)

1. Site Selection and Preparation:

  • Location: Select a location with consistent wind speeds and minimal obstructions. The turbine should ideally be installed at a height where wind speeds are higher and less turbulent.
  • Foundation: A concrete or steel foundation is prepared to provide stability for the tower and the overall turbine system.

2. Assembling the Vertical Axis Wind Turbine Components:

  1. Blades:

    • Assembly: Attach the blades to the central shaft or rotor. VAWT blades may come in a variety of shapes (e.g., straight, curved, or helical). Ensure the blades are balanced to avoid uneven loading during rotation.
    • Material: Blades are typically made of lightweight, durable materials such as fiberglass or composite plastics.

  2. Shaft:

    • Installation: The central shaft connects the blades to the generator. Ensure that the shaft is securely fixed and can rotate freely without any obstruction.

  3. Generator:

    • Connection: The generator is connected to the shaft either directly or through a gearbox, which adjusts the rotational speed to match the optimal speed for generating electricity.
    • Testing: Before mounting, test the generator to confirm it produces the desired electrical output.

  4. Tower (Support Structure):

    • Assembly: The tower must be sturdy enough to support the weight and rotation of the turbine. Install the tower at the correct height to maximize wind capture.
    • Positioning: The turbine can be mounted on a vertical pole, with the blades fixed to the top of the pole.
    • Foundation: Ensure the foundation is anchored to the ground securely.

  5. Electrical System:

    • Wiring: Connect the electrical output from the generator to the inverter, which converts the generated DC voltage to AC for household use. Proper wiring and grounding must be done according to local electrical codes.

  6. Safety Check:

    • Inspection: Inspect the entire system to ensure proper alignment, free rotation of the blades, and secure wiring.

  7. Testing:

    • Start-Up: Test the wind turbine at low wind speeds and gradually increase the wind speed. Monitor the turbine’s performance and check for any vibrations, noises, or imbalances in the rotor system.

Assembly of Horizontal Axis Wind Turbine (HAWT)

1. Site Selection and Preparation:

  • Location: Choose an open area with consistent wind flow. HAWTs typically require more space than VAWTs to accommodate the large blades and yaw mechanisms.
  • Foundation: The foundation should be solid enough to hold the weight and stress exerted by the turbine.

2. Assembling the Horizontal Axis Wind Turbine Components:

  1. Blades:

    • Blade Mounting: Attach the aerodynamic blades to the rotor hub. The number of blades can vary, but most small turbines use 3 blades. Ensure the blades are securely fastened and properly aligned to minimize vibrations.
    • Material: Blades are usually made from fiberglass, carbon fiber, or composite materials.

  2. Rotor Hub:

    • Assembly: The rotor hub is connected to the shaft and supports the blades. The rotor hub should be carefully aligned to prevent any misalignment during rotation.

  3. Main Shaft:

    • Installation: The main shaft connects the rotor hub to the generator. It is typically positioned horizontally and should be aligned to reduce mechanical strain and friction.

  4. Yaw Mechanism:

    • Installation: The yaw mechanism involves a tail or vane that adjusts the orientation of the turbine to face the wind direction. The tail vane should be attached securely to the turbine nacelle.
    • Motor and Gearbox: If applicable, install the yaw motor and gearbox to automate the orientation.

  5. Generator:

    • Connection: Attach the generator to the main shaft. Ensure that the shaft and generator are connected either directly or through a gearbox, depending on the turbine design.
    • Testing: Before final assembly, test the generator to ensure it produces the expected electrical output.

  6. Tower:

    • Assembly: The tower should be tall enough to reach optimal wind speeds, usually around 10-20 meters for small turbines. The tower structure must be able to withstand the wind forces exerted on the blades.
    • Mounting: Install the nacelle (housing for the generator and mechanical parts) on top of the tower, ensuring all components are properly secured.

  7. Electrical System:

    • Wiring: Connect the electrical output from the generator to the inverter and then to the grid or battery storage system. Proper grounding and wiring are essential to prevent electrical hazards.
    • Monitoring: Install a monitoring system to check the turbine’s performance, such as power output, speed, and operational efficiency.

  8. Safety Check:

    • Inspection: Perform a thorough inspection of the assembly to ensure that all parts are securely fastened, and that there is no risk of mechanical failure or electrical hazards.

  9. Testing:

    • Wind Testing: Test the wind turbine by starting it up in low wind conditions and gradually increasing wind speeds. Monitor the performance and adjust the yaw mechanism, if necessary.

Considerations for Wind Turbine Assembly:

  1. Wind Conditions: Before assembly, ensure that the location chosen has the appropriate wind conditions. Small wind turbines generally perform well in regions with average annual wind speeds of 5-6 m/s.
  2. Maintenance: Regular maintenance is necessary to ensure the longevity and efficiency of the wind turbine. Inspect for wear and tear on the blades, mechanical components, and electrical systems.
  3. Electrical Safety: Ensure proper grounding, wiring, and protection against over-voltage and other electrical hazards.
  4. Noise and Vibration: Minimize noise and vibration through balanced blade mounting and secure component installation.

Conclusion:

The assembly of small wind turbines (both Vertical Axis Wind Turbines (VAWTs) and Horizontal Axis Wind Turbines (HAWTs)) involves the careful installation of key components such as blades, shafts, generators, towers, and electrical systems. While VAWTs are simpler to assemble and can capture wind from any direction, HAWTs typically provide higher efficiency but require a yaw mechanism to face the wind direction. Proper site preparation, assembly techniques, and safety measures are essential for the successful installation and operation of a small wind turbine system. Regular testing and maintenance will ensure that the turbine produces a steady supply of electricity for residential or small-scale power generation applications.